A ball of mass 
is at rest on a horizontal floor.
Calculate the magnitude of the normal contact force from the floor acting on the ball.
Explain your working in (i).
The ball is now lifted above the floor and dropped so that it falls vertically,
Just before contact with the floor, the ball has velocity 
downwards. The ball bounces from the floor and its velocity just after losing contact with the floor is 
upwards. The ball is in contact with the floor for 
.
State Newton’s second law of motion.
Calculate the average resultant force on the ball when it is in contact with the floor.
.
