Answer: First option
Explanation: The higher the frequency, the higher the energy.
λν=c where λ is the wavelength, ν is the frequency and c is the speed of light. So when wavelength decreases, v increases and so does energy.
An AM radio wave has a very long wavelength. It therefore has a very low frequency and low energy.
A light wave has a very short wavelength. It therefore has a high frequency and high energy.
Answer:
<h2>the car must move with the speed</h2><h2>

</h2>
Explanation:
As we know that the momentum of the car and truck is same
so as per the formula of momentum we have

so we have

so we will have


So the car must move with the speed

We know, Speed = Wavelength * Frequency
Speed = 32.4 * 3
Speed = 97.2 m/s
So, option D is your correct answer.
Hope it helped.
Answer:

Explanation:
The initial velocity of the ball is
u = +25.9 m/s (towards the wall)
while the final velocity of the ball is
v = -21.3157 m/s (away from the wall)
The time taken for the change in velocity to occur is
t = 0.0133 s
The acceleration can be calculated as the change in velocity divided by the time taken:

Substituting the numbers, we find:

Answer:

Explanation:
It is given that,
Mass of the grindstone, m = 3 kg
Radius of the grindstone, r = 8 cm = 0.08 m
Initial speed of the grindstone, 
Finally it shuts off, 
Time taken, t = 10 s
Let
is the angular acceleration of the grindstone. Using the formula of rotational kinematics as :



Let
is the number of revolutions of the grindstone after the power is shut off. Now using the third equation of rotational kinematics as :





or

So, the number of revolutions of the grindstone after the power is shut off is 50.