friction is a force
a. that helps two objects move faster when they are touching.
b. that operates against motion when two objects are touching.
c. that gets stronger when two objects move away from each other.
d. that exists between any two objects in the universe.
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A device consisting of a wheel over which rope or chain is pulled in order to lift a heavy object.

Examples- Elevators use multiple pulleys in order to function. A cargo lift system that allows for items to be hoisted to higher floors is a pulley system

A chemical reaction is the only way to separate a pure substance because in terms of chemical composition, an element can't be broken down any more further, or separated. Some mixtures and solutions can be broken down with physical means, not just chemical reactions.

A Pure substance is only separated by a process of chemical reaction.

Pure substances are composed of only one kind of particle and have a constant or unchanging structure.

Elements and compounds are subclasses of pure substances:

An element is a substance that only contains one kind or class of atoms. An element is a pure material if it cannot be broken down or converted into other compounds by physical or chemical mechanisms. Metals, nonmetals, or metalloids make up the vast bulk of elements.

On the other hand, when two or more elements are chemically combined in a specific ratio, compounds can also be considered pure substances. However, these substances can be split up into their component parts through chemical processes.

To break down pure substances (elements and compounds) into their individual atoms or elements, a chemical reaction must take place.

Physical techniques cannot distinguish between pure substances.

Hence, Pure substance is only separated by a process of chemical reaction.

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D: use of linear perspective

The renaissance technique  used in this painting to make it more realistic and three-dimensional was use of linear perspective. Hence, option D is correct.

Creating the appearance of depth on a flat surface through the use of linear perspective. In a painting or drawing that employs this approach, all orthogonal parallel lines meet at a single vanishing point on the horizon.

It is believed that Italian Renaissance builder Filippo Brunelleschi developed linear perspective in 1415, and writer and architect Leon Battista Alberti later recorded it around 1435. They used the concept to create 3D paintings.

Although painters and architects in the ancient Greek and Roman eras were probably aware of linear perspective, there are no records from those times, and the technique was thus forgotten until the 15th century. Hence, option D is correct.

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The options of your question includes:

use of negative space

B.

use of colorful paint colors

C.

use of gesture drawing

D.

use of linear perspective

Answer:

B. 45 km/hr south

Explanation:

Velocity is a vector quantity which consists of:

- A magnitude, given by the ratio between displacement and time taken for the motion

- A direction, which corresponds to the direction of the displacement

Let's analyze now each option:

A. 12 m/s --> this is not a velocity: this is a speed, because it does not specify the direction, so it is only a scalar quantity

45 km/hr south --> this is a velocity, because it specificies both magnitude (45 km/h) and direction (south)

C. 55 km/hr  --> again ,this is not a velocity, but it is a speed, because it does not specify the direction, so it is only a scalar quantity

D. -5 m/s2 east --> this is not a velocity, but it is an acceleration, since the units of measurement are the ones of acceleration (m/s^2, while for the velocity should be m/s or km/h)

Final answer:

Velocity is a vector quantity that combines speed and direction, with option B. 45 km/hr south representing an example of velocity.

Explanation:

Velocity is a vector quantity that includes both speed and direction. In the given options, choice B. 45 km/hr south is an example of velocity because it includes both a numerical value (magnitude) and a specified direction. The question posed concerns determining which of the given options is an example of velocity. Velocity is defined as a vector quantity that describes both the speed of an object and the direction in which it is moving. Therefore, among the provided options, the one that includes both a magnitude and a specific direction should be considered an example of velocity.

The correct answer is (c) The taller the wavelength the lower the sound.

The wavelength of a sound wave affects its pitch by determining the frequency. Longer wavelengths result in lower pitch, while shorter wavelengths result in higher pitch.

Wavelength affects the pitch of a sound by influencing its frequency. Longer sound waves have lower frequency and produce a lower pitch, whereas shorter waves have higher frequency and a higher pitch. This relationship is evident in the correlation between the size of musical instruments and their pitch.

a/b. The ball has velocity vector at time [tex]t[/tex]

[tex]\vec v=(v_x,v_y)=(v_0\cos63^\circ,v_0\sin63^\circ-gt)[/tex]

where [tex]v_0=16\dfrac{\rm m}{\rm s}[/tex] is the ball's initial speed and [tex]g=9.8\dfrac{\rm m}{\mathrm s^2}[/tex].

c. At its highest point, the ball has 0 vertical speed. This occurs when

[tex]v_0\sin63^\circ-gt=0\implies t=1.5\,\mathrm s[/tex]

d. Recall that

[tex]{v_y}^2-{v_{0y}}^2=-2g\Delta y[/tex]

so that at its highest point,

[tex]0^2-(v_0\sin63^\circ)^2=-2g\Delta y\implies\Delta y=10\,\mathrm m[/tex]

e. This is just twice the time it takes for the ball to reach its maximum height, [tex]t=2.9\,\mathrm s[/tex].

f. The ball's horizontal position after time [tex]t[/tex] is

[tex]v_0\cos63^\circ\,t[/tex]

so that after the time found in part (f), the ball has traveled

[tex]v_0\cos63^\circ(2.9\,\mathrm s)=11\,\mathrm m[/tex]

The soccer ball's horizontal and vertical components of velocity are approximately 7.26 m/s and 14.25 m/s, respectively. It takes approximately 1.453 seconds to reach the highest point and the total time in the air is about 2.906 seconds. The maximum height is around 10.35 meters and the ball lands about 21.1 meters from the soccer player.

The student is dealing with a projectile motion problem which can be solved using the kinematic equations of motion and trigonometry. The given initial speed is 16 m/s, and the angle of projection is 63 degrees.

A. Horizontal component of the velocity: Using trigonometry, horizontal component = initial velocity X cos(angle).

[tex]V_{x} = 16 X cos(63^{0})\\ V_{x} = 7.26 m/s[/tex]

B. Vertical component of the velocity: Again using trigonometry, vertical component = initial velocity X sin(angle).
[tex]V_{y}=16 X sin(63^{0} )\\V_{y} = 14.25m/s[/tex]

C. Time to reach the highest point: The time to reach the highest point is calculated using the vertical component of velocity and acceleration due to gravity (g = 9.81 [tex]m/s^2[/tex]).

Using the equation[tex]V_{y} = g X t,[/tex] where t is time, we get [tex]t = \frac{V_{y}}{g}[/tex]
[tex]t = \frac{14.25 m/s}{ 9.81 m/s^2}[/tex]

t = 1.453 seconds.

D. Maximum height of the ball: The maximum height can be computed using the vertical component and time to reach the highest point. Using the equation [tex]H = \frac{Vy X t}{2}[/tex],  we get

[tex]H = \frac{14.25 m/s X 1.453 s}{2}.[/tex]
H = 10.35 m

E. Total time the ball is in the air: The ball takes the same time to go up as to come down, so the total time is twice the time to reach the highest point. T = 2 X 1.453 s = 2.906 seconds.

F. Distance from the player when it lands: Using the horizontal component of velocity and the total time in air, the range can be calculated. [tex]R = Vx X T[/tex]
R = 7.26 m/s X 2.906 seconds

R = 21.1 meters

The temperature in which water is frozen.

The freezing point is the temperature at which a liquid becomes a solid, and 'freezing' is the term for this phase transition. 'Freezing point depression' is the lowering of this temperature due to the presence of a solute. Freeze drying is a related process that involves lowering atmospheric pressure to dry and cool substances.

The freezing point is scientifically defined as the temperature at which a liquid turns into a solid. During this process, known as freezing, the physical state of the matter changes due to a decrease in temperature. An important concept related to this is freezing point depression, which refers to the lowering of a liquid's freezing point by the addition of a solute.

Substances can also undergo a process called freeze drying. This method involves drying substances such as food by reducing the atmospheric pressure around them, which speeds up the drying process and decreases the temperature of the substance being freeze-dried due to the change in pressure.

Hang time = 3.0 s

Range  = 65.06 m

Maximum Height = 11.05 m

Hang time is given by the formula;

T = 2vₒsinθ/g

Thus;

T = 2*(26.2 )sin34.2 / 9.81

    = 3.0 s  

Range is given by the formula;

R = vₒ²sin2θ/g

      = 26.2²sin(2*34.2) /9.81

      = 65.06 m  

Max height is given by the formula;

H = vₒ²sin²θ/2g

Thus;

H= 26.2²sin²34.2 /(2*9.81)

  = 11.05 m

Answer:

It means that when water has the thermal capacity equal to iron, that thermal capacity is greater than that of copper.

Explanation:

The water equivalence of a body is the body of water that has the same thermal capacity as the body, that is, it is the body of water that, receiving the same amount of heat, undergoes the same temperature variation as the body. Thus, we can say that water equivalent to iron is greater than copper means that when water has the same thermal capacity as iron, that thermal capacity is greater than that of copper.

In physics, acceleration is defined as the rate of change of the velocity of an object with respect to time. That is A = VF - VI /T;

Where A =  Acceleration

VF = Final velocity = 20 km

VI = Initial velocity = 80 km

T= Time = 0.5 hr

A = (20 - 80)/ 0.5 = - 60/.5

A = - 120 Km/ hr^2

Therefore, the acceleration of the car is -120 km/hr^2.

Because the value is negative, the appropriate name that describe it is deceleration.

NaOH is the chemical formula which represents the lye correctly.

Answer: Option D

Explanation:

Lye is termed for molecules made up of metal hydroxide family. As the compound is a metal hydroxide, it should be a base and an alkali according to the properties of metal and OH group. Mostly lye is obtained by leaching ashes or derived from strong alkali metal hydroxides.

So among the given choices, NaOH is the correct option as it is the chemical formula for sodium hydroxide. It is well known that sodium hydroxide is one of the efficient base metal in the alkali group and they can be also termed as caustic soda. Thus NaOH is the chemical formula which represents the lye correctly.

Formulate conclusions.  

The answer to this is A, Magnetic Field.

Final answer:

The correct answer is A.) Magnetic Field. An electric current creates a magnetic field, and this phenomenon is fundamental to electromagnetism. The magnetic field around a current-carrying wire can be visualized using the right-hand rule.

Explanation:

As an electric current forms an electric field, a magnetic field is created in the phenomenon of electromagnetism. Moving electric charges form an electric current and this current is the source of all magnetic fields, whether macroscopic and flowing through a wire, or microscopic and flowing in orbit around an atomic nucleus.

The creation of a magnetic field can be observed around wires carrying electrical currents, as currents are streams of charged particles moving. The magnetic field at a point in space due to an electric current flowing through a long, straight wire can be determined by the right-hand rule, which helps visualize the relationship between current and magnetic field direction around the wire.

Therefore, the correct answer is A.) Magnetic Field.

The answer is C.Magnetic Field.

Fuses and Circuit Breakers (CB) are used for the protection of power system. These along with other protective equipment like relays, isolater, switches, are collectively called as switchgear(switching equipment used in power systems).

The basic function is to break the circuit in case of faulty conditions so as to protect the power system equipment and auxiliaries.

FUSE is a low resistance device which is placed in the circuit for protection. Under faulty conditions when the current becomes more than the desired value, then due to the increase in temperature the fuse wire melts and breaks, thus breaking the circuit. These are used for lower power ratings and can be used only once, after that it has to be replaced with a new one.

CIRCUIT BREAKER also solves the same purpose i.e. it breaks the circuit when the fault occurs. These are used for large ratings and in the power systems and auxiliaries. CB also has the capability to re-close after the fault is through i.e. when the system gets healthy. The CB has two parts/contacts one is static and the other is moving(the one responsible for making or breaking the contacts).When the contacts of CB separate, then it said to have tripped. Tripping of the circuit breaker has to be very fast so as to avoid the arc formation between the two contacts, otherwise it will defeat the purpose of installing the CB. The trip signal is given to the CB by an other protective device called as an ELECTRICAL RELAY. CB’s are categorized on the basis of the power ratings and the medium used to extinguish the arc formed during the breaking of the contacts.

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Electric fuse and a Circuit breaker both contain ways to interrupt the flow of electricity.

Hope this helps!

Davinia.

Heart rate is the rate at which the heart beats per minute. It is a very important function of the human body. After doing exercise heart rate is elevated you need to gradually get it to normal.

The heart rate is the number of times the heartbeats per minute.

During training, the heart will speed up. The highest heart rate is varying which is relying on age.

The role of the heart is to accept blood that is oxygen deficient from veins and pump it to the lungs.Where it gathers up oxygen and gets freed of carbon dioxide.  

The main function of blood is to pump the blood into different portions of the body.

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B the desert was once covered in water

Answer: The answer is B.

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Answer : Deposition takes place when the molecules settle out of a solution.

Explanation :

Deposition : It is a type of process in which the phase changes from gaseous state to solid state without passing through the liquid state at constant temperature.

Or we can say that in deposition process, the molecules are settle down at the bottom of the container. In this process, there is no intermolecular space present between the atoms of molecule.

the temperature and how far it is.

if it has the lowest surface temperature, it is red.

if it has high surface temperature, it is blue.

if you look a the earth science esrt, there is a graph stating the stars in our galaxy, the milky way, and how it far, hot/cold, and howold it is.

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The temperature of a star affects its color. Hotter stars appear bluish-white, while cooler stars appear reddish. This color variation is due to the relationship between a star's temperature and its emitted light spectrum.

A star's colour depends on its surface temperature. Stars emit a continuous spectrum of light, but temperature varies the intensity distribution across wavelengths. Wien's displacement law indicates that hotter things radiate more energy at shorter wavelengths. Redder stars are cooler, while bluish stars are hotter. Red, orange, yellow, white, and blue are the coldest to hottest star colours.

A star's chemical makeup can also affect its colour. A star's atmosphere absorbs specific wavelengths of light, creating spectral lines that may change its colour. Astronomers can determine a star's temperature, composition, and other properties by analysing its colour and spectrum.

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You could easily help yourSELF if you simply follow the instructions in the question and "Use Ohm's law" to calculate the resistance.

Ohm's Law:  Resistance = (voltage) / (current)

Resistance = (10 v) / (5 A)

Resistance = 2 ohms

When the distance between the source and the observer is DEcreasing, the observer sees light that has a shorter wavelength than the light actually had when it left the source.

It doesn't matter how the distance between them is decreasing.  The source could be moving toward the observer, the observer could be moving toward the source, or they could both be moving in a way that makes the separation between them decrease as time goes on.  The result is the same.

(When this is used in Astronomy and Astrophysics, the big trick is:  How does the observer know what the wavelength actually WAS when the light left the source ?)

Field strength = (1000 v) / (40 cm)

Field strength = (1,000 v) / (0.4 meter)

Field strength = (1,000 / 0.4) (volts/meter)

Field strength = 2,500 volts per meter

The electric field strength between two parallel charged plates, separated by 40 cm is 2500 V/m

The question given above, the following data were obtaines:

The electric field strength can be obtained as shown below:

Electric field strength (E) = Potential difference (V) / Distance apart (d)

= 1000 / 0.40

= 2500 V/m

Thus, the electric field strength between the two plates is 2500 V/m

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Answer:

uthe th

Explanation:

The correct answer would be A) the lenses of the eye change the size of images

The human retina can detect objects larger than itself through the lenses of the eye and interpretation by the brain.

The small human retina can detect objects larger than itself through a complex process involving the lenses of the eye and the interpretation by the brain. The lenses of the eye focus the incoming light onto the retina, creating an image that is larger than the retina itself. The retina then captures this image and sends signals to the brain, which interprets the size of the image based on the information received from the retina.

So, the correct answer to the question is a. Lenses of the eye change the size of the images. The lenses of the eye help the small retina capture and process larger images, allowing us to see objects that are larger than our retina.

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Plasma is known as the 4th state of matter and is itself ionized gas. In this sense, ionization consists of the production of ions, which are electrically charged atoms or molecules due to the excess or lack of electrons with respect to a neutral atom or molecule.

That is why in this process there are always free electrons. Therefore in heating gas to create plasma can yield  free electrons, and the correct option is D.

Answer:

D) free electrons.      

Explanation:

Plasma is the fourth state of matter where in matter exists in ionized form. When a gas is heated such that electrons separate from the atom and positive ion is formed along free electrons, a plasma is said to be created. Example: Sun is a ball of plasma. Thus, heating a a gas to create plasma can yield free electrons. Option D is correct.

Answer:

12,558 J

Explanation:

The amount of heat absorbed by the water is given by:

[tex]Q=mC_S \Delta T[/tex]

where

m = 50 g is the mass of the water

[tex]C_s = 4.186 J/gC[/tex] is the water specific heat

[tex]\Delta T=90C-30C=60^{\circ}C[/tex] is the temperature increase of the water

Substituting into the formula, we find

[tex]Q=(50.0 g)(4.186 J/gC)(60^{\circ}C)=12,558 J[/tex]

To find the amount of heat absorbed by the water, we use the formula for heat calculation q = m × c × ΔT. With a known heat capacity of water mass and temperature change we find the heat absorbed is 12552 J.

To calculate the quantity of heat absorbed by the water, we use the formula for heat (q) which is q = m × c × ΔT . In this equation, 'm' stands for mass, 'c' represents the specific heat capacity, and 'ΔT' is the change in temperature.

 The specific heat capacity (c) of water is 4.184 J/g °C, the change in temperature (ΔT) is 90°C - 30°C = 60°C, and the mass (m) of water is 50g. Substituting these values into our formula:

 q = 50g × 4.184 J/g °C × 60°C

q = 12552 J

This value represents the heat absorbed by the water.

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Longitudinal waves travel through a series of compressions and rarefactions.

Longitudinal waves travel through a series of compressions and rarefactions, with sound waves in air and water as common examples. The motion of disturbance is in the same directoin as the wave propagates. The speed of these waves depends on the physical properties of the medium they are travelling through.

Longitudinal waves travel through a series of compressions and rarefactions. This is unlike transverse waves which have their disturbances occurring perpendicular to the direction of wave propagation. In a longitudinal wave, the disturbance or vibration is in the same direction as the wave travel. Examples of this type of wave include sound waves in air and water, seismic P-waves, and any waves where periodic variations in pressure are transmitted in fluids. The speed of these waves can depend on aspects such as the density and bulk modulus of the medium they're travelling through.

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Answer: 1) Ectothermic animals need the warmth before they can move around to hunt food.

2) frogs, lizards, snakes

3) rattle snake

4) mammals; warm-blooded

5) Ectothermic animals have a lower body temperature than endothermic animals.

6) move around faster to raise its body temperature.

7) keep their bodies from having too much water.

8) constantly move around to keep their bodies warm.

9) ectotherm

10) Homeothermy is the ability of an organism to maintain a constant internal body temperature, regardless of the temperature of the environment. This may require the ability to lose excess heat as well as the ability to generate and conserve heat. Most mammals have both abilities.

Explanation: I never ask, but can you pls give me brainlest?

The correct answer is option D) Ectothermic animals need warmth before they can move around to hunt food. The correct answer is option C) frogs, lizards, and snakes. The correct answer is option C) rattlesnake. The correct answer is option C) mammals; cold-blooded. The correct answer is option D) Ectothermic animals have a body temperature that is the same as their environment, and endothermic animals have a constant body temperature. The correct answer is option A) slow down as a response to the cooling temperature. The correct answer is option D) generates heat loss through evaporation. The correct answer is option A) eat more often to have energy to keep a constant temperature. The correct answer is option B) endotherm. The correct answer is option B) endothermic.

The student asked why lizards bask in the sun, which group of animals could be correctly classified as ectothermic, and multiple other questions regarding endothermic and ectothermic animals. Here are the detailed answers:

1. Ectothermic species, such as lizards, need warmth to move and digest. They rely on external sources of heat, such as sun exposure, to control their body temperature, which is essential for their physiological activities.

2. Ectothermic creatures, such as frogs, lizards, and snakes, rely on external heat sources to control their body temperature, whereas endothermic animals, such as robins, squirrels, mice, bears, and wolves, do so internally.

3. Rattlesnake matches Group B reptile requirements, such as hard shells and terrestrial existence, and can be classed as terrestrial or aquatic depending on standard biological classification.

4. Birds and mammals are warm-blooded, meaning they have a constant internal body temperature that does not alter with the environment, known as endothermy, which allows them to remain active in a variety of environments.

5. Ectothermic and endothermic animals have different body temperatures. Ectothermic animals maintain a steady body temperature by relying on external heat sources, whereas endothermic species regulate their internal temperature, resulting in a constant body temperature.

6. As the temperature drops, a cold-blooded animal is likely to slow down in reaction to the decreasing temperature. Cold-blooded species, or ectotherms, rely on external heat sources to control their body temperature, therefore metabolic activities slow down in colder temperatures.

7. Sweating is one way that warm-blooded animals generate heat loss through evaporation. Warm-blooded animals lose heat by evaporation, which allows moisture on their skin to evaporate, lowering and regulating the body temperature, especially in warm surroundings or during physical effort.

8. Because endothermic animals must maintain a constant body temperature, they must eat more often to have energy to keep a constant temperature. Endotherms need a high metabolic rate to maintain their internal heat generation. Regular feeding supplies the energy required to maintain a consistent body temperature, particularly in cooler regions.

9. The characteristics of Group A describe endotherms. Endotherms are organisms that can maintain a steady internal body temperature regardless of their external environment. They regulate their temperature, allowing them to flourish in a wide range of environmental conditions, as opposed to ectotherms, which rely on external heat sources.

10. The ability of some animals to modulate their body temperatures through internal techniques such as muscle shaking, fat burning, and panting is called endothermic. Endothermic species regulate their body temperature internally via metabolic processes, allowing them to maintain a steady temperature despite environmental disturbances.