PHYSICAL CHANGES :
Melting an ice cube.
Boiling water.
Mixing sand and water.
Breaking a glass.
CHEMICAL CHANGES :
Digesting food.
Cooking an egg.
Heating sugar to form caramel.
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 and Explanation:
The ball is bouncing to a height of 1/3 of its previous height this is a type of geometric sequence the total distance can be found by the sum of geometric sequence
For example let the initial height is 243 fit
After one bounce it will reach 243/3 =81 feet
After second bounce 81/3=27 feet
After third bounce 27/3 =9 feet
After fourth bounce 9/3 =3 feet
So a sequence is formed that is 243,81,27,9,3..........
Here 
Sum of infinite GP = 
From this formula we can find the total distance traveled by the ball
Acceleration = force / mass.
A = 100/50 = 2 m/s^2 .