The rate constant of a first-order process that has a half-life of 3.50 min is __________ s-1.

Final answer:

To determine the height above a window a flowerpot reached, we use kinematic equations for motion under gravity. By dividing the time the pot was in view by 2, and knowing the window's height, we calculate the initial velocity and then the additional height the pot reached above the window.

Explanation:

The question concerns a flowerpot moving past a window and how high it goes above the window after being in view for 0.49 seconds. To solve this, we can use kinematic equations of motion under constant acceleration due to gravity. We assume the pot goes up and then comes down passing the window twice, once going up and once going down. The time it takes to pass the window should be the same in both directions.

Divide the total time in view by 2 to find the time for one pass: 0.49 s / 2 = 0.245 s. Next, use the kinematic equation s = ut + 1/2at^2, where s is the distance, u is the initial velocity (0 m/s at the top of the window for the upward direction), a is the acceleration (gravity, which is -9.8 m/s^2 here), and t is the time the pot is in view. We can calculate the initial velocity needed to reach the top of the window in 0.245 s and then use that to find how high above the window top the flowerpot went.

Since the flowerpot was seen passing the entire height of the window (1.80 m), we use this distance to find the initial velocity it had when it first appeared at the bottom of the window. Using the kinematic formula u = (s - 1/2at^2) / t, we can solve for u. Then, apply this as the final velocity in the equation for its journey starting from the top of the window on its way up. With the final velocity at the top being zero (at the peak of its trajectory), we can now find the displacement above the window using the kinematic formula s = ut - 1/2at^2, and solve for s, where this time u is our previously calculated initial velocity and a is -9.8 m/s^2 (upward direction).

Answer:

The third answer is correct:)

Explanation:

X-rays are high energy electrons that can cause damage when exposed under extreme conditions. The best technology that can block it is using a lightweight type of metal foam. It can take in high energy collisions which also exhibits high forces. it does not only block x-rays but also, neutron radiation and gamma rays.

Final answer:

During the electrolysis of molten potassium bromide, the half-reaction that occurs at the cathode is the reduction of potassium ions (K+) to form potassium metal (K).

Explanation:

The half-reaction that occurs at the cathode during the electrolysis of molten potassium bromide is the reduction of potassium ions (K+) to form potassium metal (K).

The half-reaction can be represented as:

2K+ + 2e- -> 2K

At the cathode, positive ions are reduced and gain electrons to form neutral atoms or molecules.

The average velocity can be calculated using the formula:

v = d / t

For the 1st car, the velocity is calculated as:

v1 = 8.60 m / 1.80 s = 4.78 m / s

While that of the 2nd car is:

v2 = 8.60 m / 1.66 s = 5.18 m / s

Now we can solve for the acceleration using the formula:

v2^2 = v1^2 + 2 a d

Rewriting in terms of a:

a = (v2^2 – v1^2) / 2 d

a = (5.18^2 – 4.78^2) / (2 * 8.6)

a = 0.23 m/s

Therefore the train has a constant acceleration of about 0.23 meters per second.

Gauss law states that the electric flux through any closed surface is proportional to the net electric charge inside the surface. This is expressed mathematically in the form of:

Φ = Q / εo

Where,

Φ = the electric flux = unknown (which we have to find for)

Q = the net electric charge = 5.0 µC = 5 E-6 C

εo = the permittivity of free space = a constant value = 8.85 E-12 C^2 / N m^2

Plugging in the values into the equation will result in:

Φ = 5 E-6 C / (8.85 E-12 C^2 / N m^2)

Φ = 564,971.75 Wb = 5.6 x 10^5 Wb 

Answer:

1.09

Explanation:

By dividing the temperature by two and adding 30 to the result, you can convert a temperature in Celsius to Fahrenheit. You will receive a rough temperature in Fahrenheit from this.

For more accurate temperature measurements, use Fahrenheit. Additionally, it is preferable since people are more concerned about air temperature than water temperature.

Because of these factors, we ought to embrace Fahrenheit as a unit of temperature measurement rather than reject it in favor of its metric equivalent.

Fahrenheit and Celsius temperature scales are seen on the majority of thermometers. Read the °F figures (degrees of Fahrenheit).

Therefore, To get a more accurate approximation, multiply the temperature by 2, take out 10%, and then add 32 to the result.

Learn more about thermometer here:

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Answer:D

Explanation:

Motorola connecter or a Motorola antenna plug is a connector used on a car radio antenna. It is a common coaxial cable RF connector used mainly in the locomotive trade for linking coaxial feed line from the antenna to the radio receiver. The pin of the connector is fused to the middle of the conductor of the coaxial cable starting the antenna. Its adjacent ground forms a 1.5inch long sleeve all over the coax. By rubbing the male plug alongside the female socket, the sleeve contains one or more longitudinal spring that offer sufficient electrical contact.

The connector on a car radio antenna is typically attached to the base of the antenna rod, facilitating the transmission and reception of radio waves.

The connector on a car radio antenna is typically attached to the base of the antenna rod.

The rod of the antenna is fed by a coaxial cable, where the center conductor is connected to the base of the rod, and the sheath is attached to the car body.

Antennas on cars, such as the commonly seen whip antenna, are important for converting electric power into radio waves for transmission and reception.

Answer:

C. Gravity = air resistance

Explanation:

An object falling down has two forces acting on him:

- Gravity, which acts downward --> the magnitude of this force is constant (equal to [tex]mg[/tex], where m is the mass of the object and g is the gravitational acceleration)

- Air resistance, which acts upward --> the magnitude of this force is directly proportional to v, the speed of the object

When the object starts its fall, the speed is zero (v=0) so only gravity acts and it accelerates the object downward. Therefore, the speed of the object increases, and so does the air resistance, until a point where the air resistance becomes equal to gravity (which is constant): when this occurs, the acceleration of the object becomes zero (because forces are balanced), so the object continues its fall at constant velocity, called terminal velocity.

The energy of one photon of light with a wavelength of 445 nm can be calculated using Planck's equation, E = hv. This requires converting the wavelength to frequency using c = wavelength times frequency, and then substituting the frequency back into Planck's equation. The energy of one photon of 445 nm blue light is approximately 4.47 x 10^-19 Joules.

To determine the energy of one photon of light with a wavelength of 445 nm (visible light electromagnetic radiation), we can use Planck's equation, which states E = hv (energy equals Planck's constant times frequency). However, we must first convert wavelength to frequency via the speed of light equation (c = wavelength times frequency). After getting the frequency, we can substitute it back into the Planck's equation.

By doing these calculations, we find:

Therefore, one photon of 445 nm blue light has an energy approximately equal to 4.47 x 10^-19 Joules.

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Final answer:

To find the acceleration of a moving object after 5 seconds, given the distance function 2t/(4 + t), we first find the velocity by differentiating the distance function, then find the acceleration by differentiating the velocity. The acceleration after 5 seconds is approximately -0.022 m/[tex]s^2[/tex].

Explanation:

The question involves finding the acceleration of a moving object after 5 seconds, given that the distance it has traveled after t seconds is represented by the function 2t/(4 + t). To find the acceleration, we first need to determine the velocity function by differentiating the distance function with respect to t, and then find the acceleration by differentiating the velocity function with respect to t again.

The velocity v(t) is the first derivative of the distance function s(t) = 2t/(4 + t). Using the quotient rule for differentiation, v(t) = d/dt [2t/(4 + t)]. Calculating the derivative gives us v(t) = 8/(4 + t)^2.

The acceleration a(t) is the derivative of the velocity function. So, a(t) = d/dt [8/(4 + t)^2]. Differentiating this gives a(t) = -16/(4 + t)^3.

Plugging t = 5 into the acceleration function, a(5) = -16/(4 + 5)^3 = -16/729. Therefore, the acceleration of the object after 5 seconds is approximately -0.022 m/[tex]s^{2}[/tex], rounding to three decimal places.

Answer: B or

A solid is like the tray being shaken slowly and all the marbles moving in their positions, a liquid is like the tray being shaken and the marbles moving around it, and a gas is like the tray being shaken hard and the marbles moving vigorously around it.

Explanation:

i did the test

The work done when lifting a 185 g tomato by 17.9 m is approximately 32.5 joules, calculated using the weight of the tomato as the force and the distance it is lifted.

To calculate the work done when lifting an object, we can use the formula Work (W) = Force (F) × Distance (D) × cos(θ), where θ is the angle between the force and the displacement. In the case of lifting an object vertically, the angle is 0°, so the cosine term is 1, and the equation simplifies to W = F × D. For a 185 g tomato lifted 17.9 m, we first need to convert the mass of the tomato to kilograms by dividing by 1000, which gives us 0.185 kg. The force is equal to the weight of the tomato, which is the mass (m) multiplied by the acceleration due to gravity (g = 9.8 m/s²), F = m × g. Thus, the force is F = 0.185 kg × 9.8 m/s² = 1.813 N. The work done is then W = 1.813 N × 17.9 m = 32.463 J, which we round to 32.5 J when expressing it with three significant figures.

Answer: In a typical rear-end collision, the victim's head is accelerated faster and harder than torso.

Explanation:

When a vehicle crashes into the one in front of it then this type of collision is called rear-end collision.

The lighter part of the victim would have more acceleration than the lower heavy part of the victim. Here, the lighter part of the victim is head and the heaver part of the victim is torso.

Therefore,  in a typical rear-end collision, the victim's head is accelerated faster and harder than torso.

Answer:

greater than

Explanation:

When looking at nuclear masses, the mass of the parts is always greater than the mass of the whole.

Example with helium:

The atomic number of helium is 2, which means that it has two protons in its nucleus. The most common isotope of helium, ^4He, has two neutrons in addition to the two protons, giving it a mass number of 4. The mass of a proton is about 1.0073 atomic mass units (amu), and the mass of a neutron is about 1.0087 amu. Therefore, the total mass of the four nucleons (two protons and two neutrons) in the ^4He nucleus is:

2 protons x 1.0073 amu/proton + 2 neutrons x 1.0087 amu/neutron = 4.0314 amu

However, the actual (whole) mass of ^4He nucleus is found to be slightly less than the sum of the parts of the masses of its constituent nucleons. This means that the mass of the parts is always greater than the mass of the whole.

Answer:

Time period

Explanation:

The time taken by a wave to complete one cycle is called the time period of a wave. It is denoted by T. The number of vibration per second is called the frequency of the wave.

The relation between the time period and the frequency is inverse i.e.

[tex]T=\dfrac{1}{\nu}[/tex]

If the number of vibrations increases its time period will decrease.

Similarly, for a simple pendulum the time period to complete one cycle is :

[tex]T=2\pi\sqrt{\dfrac{l}{g}}[/tex]

l and g are length of pendulum and acceleration due to gravity.