Answer
See the figures below.
Work Step by Step
In this problem, the author asks us for 3 sketches.
a) The motion diagram of the ball when it is in contact with the ground.
b) The force diagram of the ball; whereas $F_n$ is the normal force exerted on the ball from the ground and $F_G$ is the gravitational force exerted by the ball by Earth's gravitational pull.
c) The free-body diagram of the ball.
See the figures below.
d) The motion diagram below is only when the ball is in contact with the ground. It is obvious from the force diagram that the force that makes the ball bounces off the floor is the net force exerted on it upward which is the resultant of two forces the normal force from the ground (upward) and the gravitational force from the Earth (downward).
The acceleration of the ball is always upward from the moment it touches the ground during the compression process to the moment it leaves the ground at the end of the expanding process.
