A 90g ball, initially at rest, is dropped from a height of 2.1m.
a. Calculate the net force acting on the ball.
b. Calculate the acceleration of the ball.
c. Calculate the final velocity of the ball just before it hit the ground.

a. 0.882 N b. 9.8 m/s² c. 6.42 m/s

Explanation:

a. The net force acting on the ball is its weight W = mg were m = mass of ball = 90 g = 0.090 kg and g = acceleration due to gravity = 9.8 m/s²

W = mg = 0.090 kg × 9.8 m/s² = 0.882 N

b. The acceleration = g = acceleration due to gravity = 9.8 m/s² since it is falling freely

c. Using v² = u² + 2as where v = final velocity of ball, u = initial velocity of ball = 0 m/s, a = acceleration of ball = 9.8 m/s² and s = height = 2.1 m. Substituting the values of the variables, we ave

v² = u² + 2as = 0² + 2(9.8 m/s²) × 2.1 m = 41.16

v = √41.16 = 6.42 m/s