A 100g sample of hot copper is placed in a coffee cup calorimeter containing 100 grams of water at room temperature. After some time the temperature of the water and the copper become a constant at 50˚C. Calculate the initial temperature of the copper piece. The specific heat of copper is 0.385 J/g˚C. The specific heat of liquid water is 4.184 J/g˚C.

Answers

Answer 1

Answer:

[tex]356^{\circ}C[/tex]

Explanation:

When the hot copper and the liquid water reaches equilibrium, they have the same temperature; when this happens, the amount of heat released by the copper is equal to the amount of heat absorbed by the water:

[tex]-Q_c = Q_w\\-m_c C_c (T_f-T_c) = m_w C_w (T_f-T_w)[/tex]

where

[tex]m_c = 100 g[/tex] is the mass of the copper

C_c=0.385 J/g˚C is the specific heat of copper

T_f=50˚C is the final temperature of both substances

[tex]m_w = 100 g[/tex] is the mass of the water

C_w=4.184 J/g˚C is the specific heat of the water

T_c is the initial temperature of the copper

T_w=20˚C is the initial temperature of the water (room temperature)

Solving for T_c, we find:

[tex]T_c = T_f + \frac{m_w C_w (T_f-T_w)}{m_c C_c}=50^{\circ} +\frac{(100 g)(4.184 J/gC) (50C-20C)}{(100 g)(0.385 J/gC)}=356^{\circ} C[/tex]

Answer 2
Final answer:

The equation formed from the conservation of energy principle allows you to calculate the initial temperature of the hot copper. It's important to note that the initial temperature of the copper is higher than 50˚C.

Explanation:

In order to calculate the initial temperature of the hot copper we need to understand that the total heat loss of the copper will be equal to the total heat gain of the water. This concept is the conservation of energy. Using this principle, we can set up the following equation:

Heat loss of copper = Heat gain of waterm(copper)*c(copper)*(T(initial)-50) = m(water)*c(water)*(50-T(water))

Since T(water) is the room temperature, we'll assume it's around 25˚C. So the equation becomes:

100g *0.385 J/g˚C *(T(initial)-50) = 100g * 4.184 J/g˚C * (50-25)

Solving this equation will give you the initial temperature of the copper.

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Related Questions

A single-slit diffraction pattern is formed on a distant screen. If the width of the single slit through which light passes is reduced, what happens to the width of the central bright fringe? Assume the angles involved remain small.

Answers

Answer:

The width of the central bright fringe will increase

Explanation:

In a single-slit diffraction pattern, the distance of the nth-minimum from the central maximum on the screen is given by

[tex]y=\frac{n \lambda D}{d}[/tex]

where

[tex]\lambda[/tex] is the wavelength of the wave

D is the distance of the screen from the slit

d is the width of the slit

The width of the central bright fringe is equal to twice the value of y=1 (first minimum), so:

[tex]w=2 y(n=1) = \frac{2\lambda D}{d}[/tex]

And we see that it is inversely proportional to the width of the slit: therefore, if the width of the slit is reduced, the width of the central brigh fringe will increase.

The wavelength of a wave on a string is 1.2 meters. If the speed of the wave is 60 meters/second, what is its frequency? A. 0.20 hertz B. 2.0 hertz C. 50 hertz D. 10 hertz E. 15 hertz

Answers

Answer:

50 Hz

Explanation:

The frequency of a wave is given by

[tex]f=\frac{v}{\lambda}[/tex]

where

v is the speed of the wave

[tex]\lambda[/tex] is the wavelength

In this problem,

v = 60 m/s

[tex]\lambda=1.2 m[/tex]

So the frequency is

[tex]f=\frac{60 m/s}{1.2 m}=50 Hz[/tex]

Answer:

50 hertz

Explanation:

Which of the following is the least reliable source of background information for a scientific project?

general Internet site
government Internet site
library reserve section
scientific journal

Answers

Answer:

general internet site

Explanation:

Answer:

General internet site

Explanation:

An air-track glider is attached to a spring. The glider is pulled to the right and released from rest at t=0 s. It then oscillates with a period of 2.00 s and a maximum speed of 60.0 cm/s . You may want to review (Pages 391 - 393) . Part A What is the amplitude of the oscillation? Express your answer with the appropriate units.

Answers

Final answer:

The amplitude of the oscillation is 30.0 cm.

Explanation:

The amplitude of an oscillation refers to the maximum displacement from the equilibrium position. In this case, the glider oscillates with a maximum speed of 60.0 cm/s. Since the maximum speed is achieved at the equilibrium position, we can equate it to the angular velocity multiplied by the amplitude:

vmax = ω * A

Given that the period of oscillation is 2.00 s, we can use the formula for angular velocity:

ω = 2π / T

Substituting the values:

60.0 cm/s = (2π / 2.00 s) * A

Simplifying the equation, we find that the amplitude of the oscillation is 30.0 cm.


Make the following conversion.

56.32 kL = _____ L

0.056320
0.56320
5,632
56,320

Answers

Answer:

The answer would be D 56,320

Explanation:

Which of the following objects owes its shape primarily to the gravitational force?

Select one:
a. the Sun
b. an electron orbital
c. a human being
d. an iron nucleus
e. an iron atom

Answers

Answer:

a

Explanation:

An electron, traveling at a speed of 5.90 × 10 6 5.90×106 m/s, strikes the target of an X-ray tube. Upon impact, the electron decelerates to three-quarters of its original speed, with an X-ray photon being emitted in the process. What is the wavelength of the photon?

Answers

Answer:

[tex]2.84\cdot 10^{-8} m[/tex]

Explanation:

Due to the law of conservation of energy, the energy of the emitted X-ray photon is equal to the energy lost by the electron.

The initial kinetic energy of the electron is:

[tex]K_i = \frac{1}{2}mv_i^2 = \frac{1}{2}(9.11\cdot 10^{-31}kg)(5.90\cdot 10^6 m/s)^2=1.59\cdot 10^{-17}J[/tex]

The electrons decelerates to 3/4 of its speed, so the new speed is

[tex]v_f = \frac{3}{4}v_i = \frac{3}{4}(5.90\cdot 10^6 m/s)=4.425\cdot 10^6 m/s[/tex]

So the final kinetic energy is

[tex]K_f = \frac{1}{2}mv_f^2=\frac{1}{2}(9.11 \cdot 10^{-31} kg)(4.425\cdot 10^6 m/s)^2=8.9\cdot 10^{-18} J[/tex]

So, the energy lost by the electron, which is equal to the energy of the emitted photon, is

[tex]E=K_i - K_f =1.59\cdot 10^{-17} J-8.9\cdot 10^{-18} J=7\cdot 10^{-18} J[/tex]

The wavelength of the photon is related to its energy by

[tex]\lambda=\frac{hc}{E}[/tex]

where h is the Planck constant and c the speed of light. Substituting E, we find

[tex]\lambda=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{7\cdot 10^{-18} J}=2.84\cdot 10^{-8} m[/tex]

Final answer:

To determine the wavelength of the photon emitted when an electron decelerates in an X-ray tube, we can use Planck's equation and the information given about the electron's speed.

Explanation:

When an electron decelerates, it emits electromagnetic waves known as X-rays. The wavelength of the X-ray photon can be determined using Planck's equation, E = hv, where E is energy, h is Planck's constant, and v is frequency. Given that the electron's velocity decreases to three-quarters of its original speed and the initial speed is 5.90x10^6 m/s, we can calculate the velocity of the electron after deceleration. Using this value, we can then calculate the wavelength of the photon emitted. Therefore, using the provided information, we can find the wavelength of the photon.

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The index of refraction for violet light in silica flint glass is 1.66, and that for red light is 1.62. What is the angular spread (in degrees) of visible light passing through a prism of apex angle 60.0° if the angle of incidence is 54.0°? See figure below. A triangular prism is shown. A ray of visible light moves up and to the right and is incident on the left edge of the prism. Inside the prism a rainbow of colors spreads out from the incident ray and in order from top to bottom they are red, orange, yellow, green, blue and violet. Once the rainbow leaves the prism, it continues to move down and to the right but all the colors are at slopes which are steeper than they were within the material. The rainbow is then projected onto a screen. The angular spread between the red and violet colors is indicated. A dashed line extends from the incident ray on the left to the right and the angle that this line makes with the red light ray is labeled Deviation of red light. ° (b) What If? What is the maximum angular spread (in degrees) for white light passing through this prism?

Answers

Answer:

4.2°

Explanation:

Snell’s law gives:-

n₁ sin θ₁ = n₂ sin θ₂

Given, θ₁ = 54.0°

For the refraction of violet light ( n = 1.66 ) from air to glass:

( 1.00 ) sin 54.0° = ( 1.66 ) sin θ₂₁

sin θ₂₁ = ( 1.00 / 1.66 ) sin 54.0° = 29.2

For the refraction of violet light from glass to air …  

n₂ sin θ₂ = n₃ sin θ₃₁

θ₂ = 60 -29.2 = 30.8

n₂ = 1.66

n₃ = 1

sin θ₃₁ = ( n₂ / n₃ ) sin θ₂ = n₂ sin θ₂₂ = ( 1.66 ) sin 30.8°  

θ₃₁ = sin ⁻ ¹ [ ( 1.66 ) sin 30.8° ] = 58.2°

For the refraction of red light ( n = 1.62 ) from air to glass

( 1.000 ) sin 54° = ( 1.62 ) sin θ₂

sin θ₂ = ( 1.000 / 1.62 ) sin 54°  

θ₂ = sin ⁻ ¹ [ ( 1.000 / 1.62 ) sin 54° ] = 29.95986° = 30.0°

For the refraction of red light from glass to air

n₂ sin θ₂ = n₃ sin θ₃₂

n₂ = 1.62 , θ₂ = 30° , n₃ = 1.000 …  

sin θ₃₂ = ( n₂ / n₃ ) sin θ₂ = n₂ sin θ₂ = ( 1.62 ) sin 30°

θ₃₂ = sin ⁻ ¹ [ ( 1.62 ) sin 30° ] = 54°

Angular spread =   γ = θ₃₁ - θ₃₂ = 4.2°

The angular spread in degrees of visible light passing through a prism of ap ex angle 60.0° if the angle of incidence is 54.0° is; 4.1°

What is the angular spread?

For incoming rays, sin sin θ₂ = (sin θ₁)/n

Thus;

(θ₂)_violet = sin⁻¹ ((sin 54)/1.66)

(θ₂)_violet = 29.17°

(θ₂)_red = sin⁻¹ ((sin 54)/1.62)

(θ₂)_red = 29.96°

For the outgoing ray;

(90 - θ₂) + (90 - θ₃) + 60° = 180°

Also, θ₃ = 60 - θ₂ and sin θ₄ = n sin θ₃

(θ₄)_violet = sin⁻¹ (1.66 * sin 30.83))

(θ₄)_violet = 58.29°

θ₄)_red = sin⁻¹ (1.62 * sin 30.04))

(θ₄)_red = 54.19°

The angular dispersion is the difference and so;

Angular dispersion = (θ₄)_violet - (θ₄)_red

Angular dispersion = 58.29° - 54.19°

Angular Dispersion = 4.1°

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List the main types of electromagnetic waves in order of increasing frequency. radio waves, microwaves, infrared, visible light, ultraviolet light, X-rays, gamma rays microwaves, radio waves, infrared, visible light, ultraviolet light, X-rays, gamma rays radio waves, microwaves, infrared, ultraviolet light, visible light, X-rays, gamma rays radio waves, microwaves, visible light, infrared, ultraviolet light, X-rays, gamma rays radio waves, microwaves, infrared, visible light, ultraviolet light, gamma rays, X-rays

Answers

Answer:

radio waves, microwaves, infrared, visible light, ultraviolet light, X-rays, gamma rays

Explanation:

Electromagnetic waves are oscillations of electric and magnetic fields in a direction perpendicular to the direction of motion of the wave (transverse waves). They are classified into 7 different types, according to their frequencies.

From lowest to highest frequency, we have:

Radio waves [tex]<10^9 Hz[/tex]

Microwaves [tex]10^9 Hz - 4\cdot 10^{13}Hz[/tex]

Infrared [tex]4\cdot 10^{13} - 4\cdot 10^{14} Hz[/tex]

Visible light [tex]4\cdot 10^{14} - 8\cdot 10^{14}Hz[/tex]

Ultraviolet [tex]8\cdot 10^{14} - 2.4\cdot 10^{16} Hz[/tex]

X-rays [tex]2.4\cdot 10^{16} -5 \cdot 10^{19}Hz[/tex]

Gamma rays [tex]>5\cdot 10^{19} Hz[/tex]

2. What's true about the elliptical path that the planets follow around the sun? A. A line can be drawn from the planet to the sun that sweeps out equal areas in equal times. B. A line can be drawn from the planet to the sun that follows the same curve as the ellipse. C. A scalar can be measured from the angle that the planet travels relative to the sun's orbit. D. A vector can be drawn from the center of one planet to the center of an adjacent planet

Answers

'A' is Kepler's 2nd law of planetary motion. It's the one to pick.

'B' is true, but so what ? It doesn't show anything.

'C' is nonsense.

'D' is true, but the vector doesn't show anything.

Answer:

A. A line can be drawn from the planet to the sun that sweeps out equal areas in equal times.

Explanation:

The planetary laws by Kepler define the motion of the planets. The law describes that planets revolve around the sun in elliptical paths with sun at of the focus. The line joining the sun and the planet sweeps equal areas in equal amount of time. The square of period of revolution is proportional to the cube of distance of the planet from the sun.

A parallel-plate capacitor initially has air (K= 1) between the plates. We first fullycharge it by a 12 V battery. After the battery is disconnected, we insert a dielectricbetween the plates and it completely fills the space in between. A voltmeter is placedacross the capacitor and it reads 3.6 V now.(a) Assuming that there is no charge loss during the process, what is the dielectricconstant of this material?(b) What’s the fraction of the stored energy changed by inserting the dielectric?(c) What will the voltmeter read if the dielectric is pulled partway out so that it fillsonly half of the space in between the plates?

Answers

(a) 3.33

For a capacitor with dielectric disconnected from the battery, the relationship between the voltage across the capacitor without the dielectric (V) and with the dielectric (V) is given by

[tex]V' = \frac{V}{k}[/tex]

where

k is the dielectric constant of the material

In this problem, we have

[tex]V' = 3.6 V[/tex]

[tex]V=12 V[/tex]

So we can re-arrange the formula to find the dielectric constant:

[tex]k=\frac{V}{V'}=\frac{12 V}{3.6 V}=3.33[/tex]

(b) The energy stored reduces by a factor 3.33

The energy stored in a capacitor is

[tex]U=\frac{1}{2}QV[/tex]

where

Q is the charge stored on the capacitor

V is the voltage across the capacitor

Here we can write the initial energy stored in the capacitor (without dielectric) as

[tex]U=\frac{1}{2}QV[/tex]

while after inserting the dielectric is

[tex]U'=\frac{1}{2}QV' = \frac{1}{2}Q\frac{V}{k}[/tex]

since Q, the charge, has not changed (the capacitor is disconnected, so the charge cannot flow away from the capacitor).

So the ratio between the two energies is

[tex]\frac{U'}{U}=\frac{\frac{1}{2}Q\frac{V}{k}}{\frac{1}{2}QV}=\frac{1}{k}[/tex]

which means

[tex]U' = \frac{U}{k}=\frac{U}{3.33}[/tex]

So, the energy stored has decreased by a factor 3.33.

(c) 5.5 V

Pulling the dielectric only partway so that it fills half of the space between the plates is equivalent to a system of 2 capacitors in parallel, each of them with area A/2 (where A is the original area of the plates of the capacitor), of which one of the two is filled with dielectric while the other one is not.

Calling

[tex]C=\frac{\epsilon_0 A}{d}[/tex] the initial capacitance of the capacitor without dielectric

The capacitance of the part of the capacitor of area A/2 without dielectric is

[tex]C_1 = \frac{\epsilon_0 \frac{A}{2}}{d}= \frac{C}{2}[/tex]

while the capacitance of the part of the capacitor with dielectric is

[tex]C_2 = \frac{k \epsilon_0 \frac{A}{2}}{d}= \frac{kC}{2}[/tex]

The two are in parallel, so their total capacitance is

[tex]C' = C_1 + C_2 = \frac{C}{2}+\frac{kC}{2}=(1+k)\frac{C}{2}=(1+3.33)\frac{C}{2}=2.17 C[/tex]

We also have that

[tex]V=\frac{Q}{C}=12 V[/tex] this is the initial voltage

So the final voltage will be

[tex]V' = \frac{Q}{C'}=\frac{Q}{2.17 C}=\frac{1}{2.17}V=\frac{12 V}{2.17}=5.5 V[/tex]

Final answer:

The dielectric constant of the material is 3.3 based on the voltage drop after insertion between the capacitor's plates from 12 V to 3.6 V. The insertion of the dielectric changes the stored energy to 9% of the original. With half the space filled by the dielectric, the voltmeter would read approximately 5.6 V.

Explanation:

The question concerns the concept of capacitors in physics, specifically the effects of inserting a dielectric material between the plates of a parallel-plate capacitor. Assuming that the battery has been disconnected and there is no charge loss during the process, let's address the parts of the question step by step.

(a) Dielectric constant of the material

The dielectric constant (K) of a material can be determined by the ratio of the initial voltage (Vo) to the voltage (V) after the dielectric has been inserted. Given that the initial voltage is 12 V and it drops to 3.6 V, the dielectric constant is K = Vo / V = 12 / 3.6 = 3.3. Therefore, the dielectric constant of this material is 3.3.

(b) Fraction of the stored energy changed

The stored energy in a capacitor is proportional to the square of the voltage across it. When the voltage drops due to the insertion of the dielectric, the energy stored changes by a factor of (V / Vo)2. Hence, the fraction of the energy change is (3.6 / 12)2 = 0.09, or 9% of the original stored energy.

(c) Voltmeter reading with half space filled by the dielectric

When the dielectric only fills half of the space between the plates, the effective dielectric constant becomes a weighted average of the dielectric and air (K=1). Assuming the dielectric constant of the inserted material is 3.3, and it fills half the space, the effective dielectric constant is (3.3 + 1) / 2 = 2.15. Thus, the new voltage is Vnew = Vo / Keff = 12 / 2.15 = 5.58 V. Therefore, the voltmeter will read approximately 5.6 V when the dielectric fills only half of the space between the plates.

Project Seafarer was an ambitious program to construct an enormous antenna, buried underground on a site about 10000 km2 in area. Its purpose was to transmit signals to submarines while they were deeply submerged. If the effective wavelength were 1.8 × 104 Earth radii, what would be the (a) frequency and (b) period of the radiation emitted? Ordinarily, electromagnetic radiations do not penetrate very far into conductors such as seawater. Take the Earth's radius to be 6370 km. (a) Number Enter your answer for part (a) in accordance to the question statementEntry field with incorrect answer Units Choose the answer for part (a) from the menu in accordance to the question statementEntry field with correct answer

Answers

(a) 0.0026 Hz

The relationship between frequency and wavelength for an electromagnetic wave is

[tex]f=\frac{c}{\lambda}[/tex] (1)

where

[tex]c=3.0\cdot 10^8 m/s[/tex] is the speed of light

f is the frequency

[tex]\lambda[/tex] is the wavelength

For the wave in the problem, the wavelength is [tex]1.8\cdot 10^4[/tex] Earth radii. The Earth radius is

[tex]R=6370 km = 6.37\cdot 10^6 m[/tex]

so the wavelength would be

[tex]\lambda = (1.8\cdot 10^4 )(6.37\cdot 10^6 m)=1.14\cdot 10^{11}m[/tex]

So by using eq.(1) we find the frequency:

[tex]f=\frac{3\cdot 10^8 m/s}{1.14\cdot 10^{11}m}=0.0026 Hz[/tex]

(b) 384.6 s

The period of a wave is given by:

[tex]T=\frac{1}{f}[/tex]

where

T is the period

f is the frequency

For the wave in the problem,

f = 0.0026 Hz

so the period is

[tex]T=\frac{1}{0.0026 Hz}=384.6 s[/tex]

Final answer:

To find the frequency and period of the radiation emitted by Project Seafarer, use the formula: Frequency = Speed of Light / Wavelength and Period = 1 / Frequency. Convert the effective wavelength given to kilometers and then use the formulas to calculate the frequency and period.

Explanation:

To find the frequency and period of the radiation emitted by the Project Seafarer antenna, we need to use the formula:

Frequency = Speed of Light / Wavelength

Period = 1 / Frequency

The effective wavelength given in the question is 1.8 × 104 Earth radii. We can convert this to kilometers by multiplying it by the Earth's radius of 6370 km. So the wavelength is 1.8 × 104 * 6370 = 1.1486 × 108 km.

Now we can calculate the frequency using the formula: Frequency = 3 × 108 m/s / 1.1486 × 108 km.

Finally, we can calculate the period by taking the reciprocal of the frequency.

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Gary needs to move a chair that is 20 pounds at a distance of 5 feet. How much work will he need to produce?

100 ft-lbs
80 ft-lbs
120 ft-lbs
75 ft-lbs

Answers

Hello!

The answer is:

The answer is the first option, 100 ft-lbs.

Why?

To calculate the work done by an object over a distance, we need to multiply the applied force by the amount of movement (distance).

So, to calculate the work that Gary needs to do to move the chair, we need to use the following equation:

[tex]Work=Force*Distance[/tex]

We are given,

[tex]Force=20lb\\Distance=5ft[/tex]

[tex]Work=F*D\\Work=(20lb)*(5ft)=100ft-lbs[/tex]

Hence, the answer is the first option, 100 ft-lbs.

Have a nice day!

answer- 100 ft-lbs

Hope I helped

which statement accurately describes the illustration?
A. Hydrogen has a valence of 1 and oxygen has a valence of 8
B. Hydrogen has a valence of 1 and oxygen has a valence of 2
C. Hydrogen has a valence of 2 and oxygen has a valence of 6
D. Hydrogen has a valence of 1 and oxygen has a valence of 6

Answers

Answer: A. Hydrogen has a valence of 1 and Oxygen has a valence of 8.

Explanation:

Meaning that oxygen has 8 valence electrons in its outer shell and hydrogen has 1 valence electron in its outer shell

Answer:

D. Hydrogen has a valence of 1 and oxygen has a valence of 6

Explanation:

Electrons present in the outer most shell of an atom is known as valence electrons.

Here oxygen has 6 valence electrons in its outermost shell while hydrogen has only one valence shell in its outermost shell

So here if hydrogen share its one electron with oxygen then its electron configuration becomes stable and if oxygen share its two electrons of the shell with two different hydrogen atoms then this will stable the electron configuration of oxygen.

So in this way hydrogen and oxygen forms bonds with each other and its bond sharing electrons will form bond.

so here correct answer will be

D. Hydrogen has a valence of 1 and oxygen has a valence of 6

Use Snell's Law to solve the following:

Answers

Answer:

1.171

Explanation:

if n₁sinΘ₁=n₂sinΘ₂, then n₂=n₁sinΘ₁ / sinΘ₂;

[tex]n_2=\frac{1.5*sin45}{sin65}=\frac{1.5*0.707}{0.906} =1.1705[/tex]

What is EMF?

When are we exposed to EMF?

Does EMF increase or decrease with distance?

What are the primary differences in direct current and alternating current?

Answers

Answer:

Electricity is the voltage produced by any electrical energy source such as battery or dynamo. EMF increase with distance.

The direct current is fixed but the alternating current is constantly changing

the half-life of carbon -14 is 5730 years. What fraction of carbon-14 would remain after 11,460 years?

Answers

Answer:

= 1/4

Explanation:

Half life refers to the time taken by a radioactive isotope or atom to decay by half of its original mass.

Using the formula;

N = O × (1/2)^t;

Where N is the new mass after decay, while O is the original mass of the radioactive isotope before decay, while t is the number of half lives.

Therefore;

Number of half lives = 11, 460/5730 = 2 half lives

Thus;

New fraction = 1 × (1/2)²

                      = 1/4

Therefore, the fraction that will remain after decay is 1/4 of carbon-14.

Answer:

28,650 years ago

Explanation:

right on edge

The sun is directly over the equator on what day of the year?

Answers

Answer:

The Sun Crosses the Equator. on March 19, 20, or 21 every year. The September equinox occurs the moment the Sun crosses the celestial equator, this happens either on September 22, 23, or 24 every year.

Explanation:

The Sun Crosses the Equator. on March 19, 20, or 21 every year. The September equinox occurs the moment the Sun crosses the celestial equator, this happens either on September 22, 23, or 24 every year.

Answer:

The sun is directly above the equator on the equinoxes, the spring equinox being on March 20, and the fall equinox being on September 22.

Explanation:

Bob is driving the getaway car after the big bank robbery. He's going 50 m/s when his headlights suddenly reveal a nail strip that the cops have placed across the road 120 m in front of him. If Bob can stop in time, he can throw the car into reverse and escape. But if he crosses the nail strip, all his tires will go flat and he will be caught. Bob's reaction time before he can hit the brakes is 0.7 s,and his car's maximum deceleration is 10 m/s2.Does Bob stop before or after the nail strip and by what distance?Express your answer with the appropriate units. Enter positive value if Bob stops after the nail strip and negative value if he stops before it.

Answers

Answer:

-40 m

Explanation:

First, we find the position that Bob reaches before he reacts.

x = x₀ + v₀ t + ½ at²

x = 0 m + (50 m/s) (0.7 s) + ½ (0 m/s²) (0.7 s)²

x = 35 m

Then, we find his position when he stops after deceleration.

v² = v₀² + 2a(x - x₀)

(0 m/s)² = (50 m/s)² + 2(-10 m/s²)(x - 35 m)

x = 160 m

His position relative to the nail strip is:

120 m - 160 m = -40 m

So Bob stops after the nail strip by 40 m.

Final answer:

Bob will stop after the nail strip by a distance of 40 m.

Explanation:

Using the given information, we can calculate whether Bob stops before or after the nail strip and by what distance.

First, we need to calculate the distance covered during Bob's reaction time. He is traveling at 50 m/s, and his reaction time is 0.7 s, so the distance covered is:

Distance = (Speed)(Time) = (50 m/s)(0.7 s) = 35 m

Next, we can calculate the distance it takes for Bob to stop the car. Bob's car has a maximum deceleration of 10 m/s2, so the distance covered during braking is:

Distance = (Initial Velocity^2) / (2 * Deceleration) = (50 m/s)ˆ2 / (2 * 10 m/s^2) = 125 m

Therefore, the total stopping distance is the sum of the distance covered during the reaction time and the distance covered during braking:

Total Stopping Distance = 35 m + 125 m = 160 m

Since the nail strip is 120 m in front of him, Bob will stop after the nail strip by a distance of 40 m.

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If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 477J of energy to the room?

Answers

Answer:A negative economic effect of World War II was

a global depression.

huge losses in agriculture.

millions of refugees.

millions of deaths.

Explanation: millions of deaths.

477 joules of heat was taken away from the food kept in the refrigerator.

Explanation:

According to the law of thermodynamics which is inferred from the law of energy conservation, energy can neither be created nor be destroyed but it can be transformed from one to another.

Hence when 477 j of energy was released into the room by refrigerator, it means 477 j of heat was removed from the food kept inside the refrigerator.

A team of astronauts is on a mission to land on and explore a large asteroid. In addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. With what minimum initial speed ????esc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? Assume that the asteroid is approximately spherical, with an average density ????=4.49×106 g/m3 and volume ????=3.32×1012 m3 . Recall that the universal gravitational constant is ????=6.67×10−11 N·m2/kg2 .

Answers

Answer:

463.4 m/s

Explanation:

The escape velocity on the surface of a planet/asteroid is given by

[tex]v=\sqrt{\frac{2GM}{R}}[/tex] (1)

where

G is the gravitational constant

M is the mass of the planet/asteroid

R is the radius of the planet/asteroid

For the asteroid in this problem, we know

[tex]\rho=4.49\cdot 10^6 g/m^3[/tex] is the density

[tex]V=3.32\cdot 10^{12} m^3[/tex] is the volume

So we can find its mass:

[tex]M=\frac{\rho}{V}=(4.49\cdot 10^6 g/m^3)(3.32\cdot 10^{12}m^3)=1.49\cdot 10^{19} kg[/tex]

Also, the asteroid is approximately spherical, so its volume is given by

[tex]V=\frac{4}{3}\pi R^3[/tex]

where R is the radius. Solving the formula for R, we find its radius:

[tex]R=\sqrt[3]{\frac{3V}{4\pi}}=\sqrt[3]{\frac{3(3.32\cdot 10^{12}m^3)}{4\pi}}=9256 m[/tex]

So now we can use eq.(1) to find the escape velocity:

[tex]v=\sqrt{\frac{2(6.67\cdot 10^{-11})(1.49\cdot 10^{19}kg)}{9256 m}}=463.4 m/s[/tex]

At sunset, red light travels horizontally through the doorway in the western wall of your beach cabin, and you observe the light on the eastern wall. Assume that the light has a wavelength of 700 nm, that the door is 1.0 m wide, and that the distance from the door to the far wall of your cabin in 14 m .Part ADetermine the distance between the central bright fringe and a first-order dark fringe of the interference pattern created by the doorway "slit".

Answers

Answer:

[tex]9.8\cdot 10^{-6}m[/tex]

Explanation:

For light passing through a single slit, the position of the nth-minimum from the central bright fringe in the diffraction pattern is given by

[tex]y=\frac{n \lambda D}{d}[/tex]

where

[tex]\lambda[/tex] is the wavelength

D is the distance of the screen from the slit

d is the width of the slit

In this problem, we have

[tex]\lambda=700 nm = 7.00\cdot 10^{-7}m[/tex] is the wavelength of the red light

D = 14 m is the distance of the screen from the doorway

d = 1.0 m is the width of the doorway

Substituting n=1 into the equation, we find the distance between the central bright fringe and the first-order dark fringe (the first minimum):

[tex]y=\frac{(1)(7.00\cdot 10^{-7} m)(14 m)}{1.0 m}=9.8\cdot 10^{-6}m[/tex]

Imagine two parallel, (infinite) planar sheets of perfectly black material, maintained at fixed temperatures TH and TL, respectively, and separated by some finite distance D. Suspended in between and parallel to these sheets are n additional, separate, parallel sheets of material, all with constant reflectivity r. (By separate, we mean that none of the sheets are in actual mechanical contact). When the entire system reaches a steady state, find (a) the net flux density (energy flow per unit time per unit area) of thermal radiation between the original two sheets. (b) How does this compare to the radiation flux that would be present between the two black sheets in the absence of the n intervening sheets? (c) To provide the best insulation, should these intermediate sheets be made of very shiny or very black material, or something in between?

Answers

The TIL will support your answer I believe if you just think about of the provide the inslutoin which that mean money is gong fast to the enconmomy

The speed of electromagnetic waves (which include visible light, radio, and x rays) in vacuum is 3.0 x 108 m/s. Wavelengths of visible light waves range from about 400 nm in the violet to about 700 nm in the red. What are the (a) minimum and (b) maximum frequencies of these waves? The range of frequencies for shortwave radio (for example, FM radio and VHF television) is 1.5 to 300 MHz. What are the (c) minimum and (d) maximum wavelengths of these waves? X ray wavelengths range from about 5.0 nm to about 1.0 x 10-2 nm. What are the (e) minimum and (f) maximum frequencies of x rays?

Answers

(a) [tex]4.29\cdot 10^{14}Hz[/tex]

The frequency of an electromagnetic wave is given by

[tex]f=\frac{c}{\lambda}[/tex]

where

c is the speed of light

[tex]\lambda[/tex] is the wavelength

We notice from the formula that the frequency is inversely proportional to the wavelength, so the minimum frequency corresponds to the maximum wavelength, and viceversa

The maximum value of the wavelength of the visible light waves is

[tex]\lambda_{max} = 700 nm = 7.0\cdot 10^{-7} m[/tex] (red light)

so the minimum frequency of visible light is

[tex]f_{min} = \frac{c}{\lambda_{max}}=\frac{3.0\cdot 10^8 m/s}{7.00\cdot 10^{-7}m}=4.29\cdot 10^{14}Hz[/tex]

(b) [tex]7.50\cdot 10^{14}Hz[/tex]

The maximum frequency corresponds to the minimum wavelength;

The minimum wavelength is

[tex]\lambda_{min} = 400 nm = 4.0\cdot 10^{-7} m[/tex] (violet light)

so the maximum frequency of visible light is

[tex]f_{max} = \frac{c}{\lambda_{min}}=\frac{3.0\cdot 10^8 m/s}{4.00\cdot 10^{-7}m}=7.50\cdot 10^{14}Hz[/tex]

(c) 1 m

The wavelength of an electromagnetic wave is given by

[tex]\lambda=\frac{c}{f}[/tex]

as before, we notice that the minimum wavelength corresponds to the maximum frequency, and viceversa.

The maximum frequency of shortwave radio waves is

[tex]f_{max}=300 MHz = 3.0\cdot 10^8 Hz[/tex]

so the minimum wavelength of these waves is

[tex]\lambda_{min} = \frac{c}{f_{max}}=\frac{3.0\cdot 10^8 m/s}{3.0\cdot 10^8 Hz}=1 m[/tex]

(d) 200 m

The minimum frequency of shortwave radio waves is

[tex]f_{min}=1.5 MHz = 1.5\cdot 10^6 Hz[/tex]

so the maximum wavelength of these waves is

[tex]\lambda_{max} = \frac{c}{f_{min}}=\frac{3.0\cdot 10^8 m/s}{1.5\cdot 10^6 Hz}=200 m[/tex]

(e) [tex]6.0\cdot 10^{16}Hz[/tex]

As in part (a) and (b), we can find the frequency of the X-rays by using the formula

[tex]f=\frac{c}{\lambda}[/tex]

The maximum wavelength of the x-rays is

[tex]\lambda_{max} = 5.0 nm = 5.0\cdot 10^{-9} m[/tex]

so the minimum frequency is

[tex]f_{min} = \frac{c}{\lambda_{max}}=\frac{3.0\cdot 10^8 m/s}{5.0\cdot 10^{-9}m}=6.0\cdot 10^{16}Hz[/tex]

(f) [tex]3.0\cdot 10^{19}Hz[/tex]

The maximum frequency corresponds to the minimum wavelength;

The minimum wavelength is

[tex]\lambda_{min} = 1.0\cdot 10^{-2} nm = 1.0\cdot 10^{-11} m[/tex]

so the maximum frequency of the x-rays is

[tex]f_{max} = \frac{c}{\lambda_{min}}=\frac{3.0\cdot 10^8 m/s}{1.0\cdot 10^{-11}m}=3.0\cdot 10^{19}Hz[/tex]

Final answer:

The frequency of electromagnetic waves varies inversely with the wavelength. For visible light, the frequencies range between 4.29 x 10⁹⁴ Hz and 7.5 x 10⁹⁴ Hz; for shortwave radio, the wavelengths range from 1 to 200 meters; for x-rays, the frequencies vary between 6 x 10⁹⁶ Hz and 3 x 10⁹⁹ Hz.

Explanation:

Calculating Frequency and Wavelength of Electromagnetic Waves

To calculate the frequency (ν) and wavelength (λ) of electromagnetic waves, we use the relation c = λν, where c is the speed of light in a vacuum (approximately 3.0 x 10⁸ m/s).

(a) The minimum frequency of visible light (700 nm) is obtained by c/λ, yielding approximately 4.29 x 10¹⁴ Hz.
(b) The maximum frequency for visible light (400 nm) is reached with c/λ, giving around 7.5 x 10¹⁴ Hz.

(c) The minimum wavelength for shortwave radio at 300 MHz is found by c/ν, resulting in 1 meter (m).
(d) The maximum wavelength at 1.5 MHz of shortwave radio is calculated with c/ν, equating to 200 meters (m).

(e) The minimum frequency of x-rays (1.0 x 10⁻² nm) is computed using c/λ, and is approximately 3 x 10¹⁹ Hz.
(f) The maximum frequency for x-rays (5.0 nm) is also obtained with c/λ, yielding around 6 x 10¹⁶ Hz.

What’s The Answer, To The Question In The Photo

Answers

Answer:

The correct answer is the third option: The kinetic energy of the water molecules decreases.

Explanation:

Temperature is, in depth, a statistical value; kind of an average of the particles movement in any physical system (such as a glass filled with water). Kinetic energy, for sure, is the energy resulting from movement (technically depending on mass and velocity of a system; in other words, the faster something moves, the greater its kinetic energy.

Since temperature is related to the total average random movement in a system, and so is the kinetic energy (related to movement through velocity), as the thermometer measures less temperature, that would mean that the particles (in this case: water particles) are moving slowly, so that: the slower something moves, the lower its kinetic energy.

In summary: temperature tells about how fast are moving and colliding the particles within a system, and since it is directly proportional to the amount of movement, it can be related (also directly proportional) to the kinectic energy.

A scale used to weigh fish consists of a spring hung from a support. The spring's equilibrium length is 10.0 cm. When a 4.0 kg fish is suspended from the end of the spring, it stretches to a length of 13.4 cm.

(Part A) What is the spring constant k for this spring? Express your answer with the appropriate units.
(Part B) If an 8.0 kg fish is suspended from the spring, what will be the length of the spring? Express your answer with the appropriate units.

Answers

A) 1153 N/m

We can find the spring constant by using Hooke's law:

[tex]F=kx[/tex]

where

F is the force applied to the spring

k is the spring constant

x is the displacement of the spring

In this problem, a fish of mass m = 4.0 kg is hanging on the spring, so the force applied is the weight of the fish:

[tex]F=mg=(4.0 kg)(9.8 m/s^2)=39.2 N[/tex]

and the displacement of the spring is:

[tex]x = 13.4 cm - 10.0 cm = 3.4 cm = 0.034 m[/tex]

so, the spring constant is

[tex]k=\frac{F}{x}=\frac{39.2 N}{0.034 m}=1153 N/m[/tex]

B) 16.8 cm

In this case, a fish of mass

m = 8.0 kg

is hanging on the spring. Therefore, the force applied to the spring is

[tex]F=mg=(8.0 kg)(9.8 m/s^2)=78.4 N[/tex]

So we can find the displacement of the spring:

[tex]x=\frac{F}{k}=\frac{78.4 N}{1153 N/m}=0.068 m = 6.8 cm[/tex]

And since the equilibrium length of the spring is

[tex]x_0 = 10.0 cm[/tex]

the new length of the spring will be

[tex]x' = 10.0 cm + 6.8 cm = 16.8 cm[/tex]

The spring constant of the spring is 1,152.94 N/m.

The new length of the spring when 8kg fish is suspended on it is 16.8 cm.

The given parameters;

length of the spring, L₁ = 10.0 cmmass of the fish, m = 4 kgfinal length of the spring, L₂ = 13.4 cm

The extension of the spring is calculated as follows;

x = L₂ - L₁

x = 13.4 cm - 10.0 cm

x = 3.4 cm

The spring constant of the spring is calculated as follows;

F = kx

mg = kx

[tex]k = \frac{mg}{x} \\\\k = \frac{4 \times 9.8}{0.034} \\\\k = 1,152.94 \ N/m[/tex]

The new extension of the spring when 8 kg fish is suspended on it;

[tex]x = \frac{mg}{k} \\\\x = \frac{8 \times 9.8}{1152.94} \\\\ x= 0.068 \ m\\\\x = 6.8 \ cm[/tex]

The new length of the spring = 6.8 cm + 10 cm = 16.8 cm

Learn more here:https://brainly.com/question/4404276

A standard mercury thermometer consists of a hollow glasscylinder, the stem, attached to a bulb filled with mercury. As thetemperature of the thermometer changes, the mercury expands (orcontracts) and the height of the mercury column in the stemchanges. Marks are made on the stem to denote the height of themercury column at different temperatures such as the freezing point(0 C ) and the boiling point (100 C ) of water. Othertemperature markings are interpolated between these twopoints.Due to concerns about the toxic properties of mercury,many thermometers are made with other liquids. Consider drainingthe mercury from the above thermometer and replacing it withanother, such as alcohol. Alcohol has a coefficient of volumeexpansion 5.6 times greater than that of mercury. The amount ofalcohol is adjusted such that when placed in ice water, thethermometer accurately records 0 C. No other changes are made tothe thermometer.Part AWhen the alcohol thermometer is placed in 22 C water,what temperature will the thermometer record?less than 22 C22 Cgreater than 22 CPart BWhen the alcohol thermometer is placed in a -12 Csubstance, what temperature will the thermometer record?less than-12 C-12 Cgreater than -12 CPart CIf you want to design a thermometer with the same spacingbetween temperature markings as a mercury thermometer, how must thediameter of the inner hollow cylinder of the stem of the alcoholthermometer compare to that of the mercury thermometer? Assume thatthe bulb has a much larger volume than the stem.5.6 times wider√5.6 times widerthe same diameter but different bulbsize√5.6 times smaller5.6 times smaller

Answers

Answer:

this is way too long....

Explanation:

A tennis player tosses a tennis ball straight up and then catches it after 1.77 s at the same height as the point of release. (a) What is the acceleration of the ball while it is in flight? magnitude m/s2 direction (b) What is the velocity of the ball when it reaches its maximum height? magnitude m/s direction (c) Find the initial velocity of the ball. m/s upward (d) Find the maximum height it reaches. m'

Answers

(a) 9.8 m/s^2, downward

There is only one force acting on the ball while it is in flight: the force of gravity, which is

F = mg

where

m is the mass of the ball

g is the gravitational acceleration

According to Newton's second law, the force acting on the ball is equal to the product between the mass of the ball and its acceleration, so

F = mg = ma

which means

a = g

So, the acceleration of the ball during the whole flight is equal to the acceleration of gravity:

g = -9.8 m/s^2

where the negative sign means the direction is downward.

(b) v = 0

Any object thrown upward reaches its maximum height when its velocity is zero:

v = 0

In fact, at that moment, the object's velocity is turning from upward to downward: that means that at that instant, the velocity must be zero.

(c) 8.72 m/s, upward

The initial velocity of the ball can be found by using the equation:

v = u + at

Where

v = 0 is the velocity at the maximum height

u is the initial velocity

a = g = -9.8 m/s^2 is the acceleration

t is the time at which the ball reaches the maximum height: this is half of the time it takes for the ball to reach again the starting point of the motion, so

[tex]t=\frac{1.77 s}{2}=0.89 s[/tex]

So we can now solve the equation for u, and we find:

[tex]u=v-at=0-(-9.8 m/s^2)(0.89 s)=8.72 m/s[/tex]

(d) 3.88 m

The maximum height reached by the ball can be found by using the equation:

[tex]v^2 - u^2 = 2ad[/tex]

where

v = 0 is the velocity at the maximum height

u = 8.72 m/s is the initial velocity

a = g = -9.8 m/s^2 is the gravitational acceleration

d is the maximum height reached

Solving the equation for d, we find

[tex]d=\frac{v^2-u^2}{2a}=\frac{0^2-(8.72 m/s)^2}{2(-9.8 m/s^2)}=3.88 m[/tex]

Explain how energy allows a paper clip to be attracted to a magnet

Answers

I really don’t know maybe energy from the poles just attaches and the soil comes and energy lifts the matter of soil and the magnet follows and lifts and goes up to the soil and the poles attach the magnet to the soil and the energy lifts the magnet and the soil follows and it is attracted to the magnet

The North Pole of the bar magnet lines up magnetic domains in the paper clip, in such a fashion that the domain’s South Pole are on the closer side. In the same way, the South Pole induces North Pole in the paper clip. This causes the attraction

Optical tweezers use light from a laser to move single atoms and molecules around. Suppose the intensity of light from the tweezers is 1000 W/m2, the same as the intensity of sunlight at the surface of the Earth. (a) What is the pressure on an atom if light from the tweezers is totally absorbed? ? Pa (b) If this pressure were exerted on a tritium atom, what would be its acceleration? (The mass of a tritium atom is 5.01 ✕ 10−27 kg. Assume the cross-sectional area of the laser beam is 6.65 ✕ 10−29 m2.)

Answers

(a)  [tex]3.3\cdot 10^{-6} Pa[/tex]

The radiation pressure exerted by an electromagnetic wave on a surface that totally absorbs the radiation is given by

[tex]p=\frac{I}{c}[/tex]

where

I is the intensity of the wave

c is the speed of light

In this problem,

[tex]I=1000 W/m^2[/tex]

and substituting [tex]c=3\cdot 10^8 m/s[/tex], we find the radiation pressure

[tex]p=\frac{1000 W/m^2}{3\cdot 10^8 m/s}=3.3\cdot 10^{-6}Pa[/tex]

(b) [tex]4.4\cdot 10^{-8} m/s^2[/tex]

Since we know the cross-sectional area of the laser beam:

[tex]A=6.65\cdot 10^{-29}m^2[/tex]

starting from the radiation pressure found at point (a), we can calculate the force exerted on a tritium atom:

[tex]F=pa=(3.3\cdot 10^{-6}Pa)(6.65\cdot 10^{-29} m^2)=2.2\cdot 10^{-34}N[/tex]

And then, since we know the mass of the atom

[tex]m=5.01\cdot 10^{-27}kg[/tex]

we can find the acceleration, by using Newton's second law:

[tex]a=\frac{F}{m}=\frac{2.2\cdot 10^{-34} N}{5.01\cdot 10^{-27} kg}=4.4\cdot 10^{-8} m/s^2[/tex]

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