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:
Time = 11.60 seconds.
Explanation:
Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.
Mathematically, speed is given by the equation;

Given the following data;
Speed = 0.711m/s
Distance = 8.25m
To find the time;
Making time the subject of formula, we have;
Substituting into the equation, we have;

Time = 11.60 secs.
Voltage = Current (I) × Resistance (R)
V = 10 × 28.5 = 285v
Answer:
Radio waves have a wavelength between
and 
While,
X rays have a wavelength between 1m and 10km.
=> It is one of the condition of diffraction that the obstacle (coming in the way) must be comparable with the size of the wavelength.
=> This shows, that radio waves have a wavelength which is comparable with the size of buildings and can really easily diffract through it
=> While, X-rays are big enough to diffract through the wall.
So, if an X-ray technician stands behind a wall during the use of her machine, she will remain safe.