As per the question the wavelength of the microwave is given as 3.52 mm.
we are asked to calculate the frequency of the wave.
we know that microwave is a electromagnetic wave.
As per Clark Maxwell's electromagnetic theory ,every electromagnetic wave moves with a velocity equal to the velocity of light in vacuum and that is equal to 3×10^8 m/s.
From the equation of the wave,we know that velocity of wave is the product of frequency and wavelength.
Mathematically wave velocity
where f is the frequency of the wave and
is the wavelength.
As per the question 

Here 
Hence frequency of the wave 


Here Hertz [Hz] is the unit of frequency.
Answer:
18.33 Ns
Explanation:
As the pitch back speed has the opposite direction as before, the change in velocity would be

So the change in momentum of the ball would be the product of its velocity change and its mass

This is equals to the impulse acted on the ball by the bat, which is 18.33 Ns
Answer:
The value of d is 20.4 m.
(C) is correct option.
Explanation:
Given that,
Initial velocity = 20 m/s
Final velocity = 0
We need to calculate the time
Using equation of motion

Where, u = Initial velocity
v = Final velocity
Put the value into the formula


We need to calculate the distance
Using equation of motion



Hence, The value of d is 20.4 m.
Answer:
From question (a) and (b) the pendulum motion is perpendicular to the force so the normal force will do no work and the tension in the string of the pendulum will not work

And
so

c
An example will be a where a stone is attached to the end of a string and is made to move in a circular motion while keeping the other end of the string in a fixed position
d
A dog walking along a surface which has friction, here the frictional force would acting in the direction of the motion and this would do positive work
Explanation:
Answer:
Distance, d = 0.1 m
It is given that,
Initial velocity of meson,
Finally, the meson is coming to rest v = 0
Acceleration of the meson, (opposite to initial velocity)
Using third equation of motion as :
s is the distance the meson travelled before coming to rest.
So,
s = 0.1 m
The meson will cover the distance of 0.1 m before coming to rest. Hence, this is the required solution.