To solve this problem we will use the kinematic formula for the final velocity.

The final speed is 0 at the moment the player stops.
The time until it stops is 1.3 s
The initial speed is 200 feet / s Note (check the speed units in the problem statement, 200ft / s is very much and 200ft / h is very small)
Then, we clear the formula.

Because the player is slowing down, the acceleration goes in the opposite direction to the player's movement, and that is why it is negative.
To answer part b) we use the following formula.

Answer:
They don’t ‘represent’ anything, they are properties of the wave.
Depending on the type of wave, we experience them as various phenomena. For example, with a sound wave we experience frequency (or wavelength, which is just another way to describe the same property) as the pitch of the sound. We experience amplitude as the loudness of the sound, although due to the characteristics of the ear, frequency also effects perceived loudness.
If the wave is a light wave, we experience the frequency (wavelength) as the colour of the light, and the amplitude as the brightness of the light.
For many waves, we don’t perceive them at all (e.g. radio waves).
For ocean waves, frequency is the time for each peak or trough to reach us, and amplitude is how tall the wave is.
Answer:
20.62361 rad/s
489.81804 J
Explanation:
= Initial moment of inertia = 9.3 kgm²
= Final moment of inertia = 5.1 kgm²
= Initial angular speed = 1.8 rev/s
= Final angular speed
As the angular momentum of the system is conserved

The resulting angular speed of the platform is 20.62361 rad/s
Change in kinetic energy is given by

The change in kinetic energy of the system is 489.81804 J
As the work was done to move the weight in there was an increase in kinetic energy
Answer:
Average recoil force experienced by machine will be 200 N
Explanation:
We have give mass of each bullet m = 50 gram = 0.05 kg
There are 4 bullets
So mass of 4 bullets = 4×0.05 = 0.2 kg
Initial speed of the bullet u = 0 m/sec
And final speed of the bullet v = 1000 m/sec
So change in momentum 
Time is given per second so t = 1 sec
We know that force is equal to rate of change of momentum
So force will be equal to 
So average recoil force experienced by machine will be 200 N