Bill throws a 10.0 g ball from a height of 2.00 m. The ball strikes the floor at a speed of 7.50 m/s. I can not use kinematics

Question

a) What was the maximum amount of energy achieved throughout the throw?

b) What was the maximum height of the ball?

c) What was the initial velocity of the ball?

Answer 1

(a)

The total energy is the same throughout the throw. It equals the kinetic energy when it hits the floor, which is

mv²/2 = (0.010 kg)(7.50 m/s)²/2 = ? joules

That also equals the maximum kinetic energy of the throw. Perhaps that is what you meant to ask for.

(b)

At maximum height, the total energy is potential energy, so set the result from part (a) equal to mgh, and solve for h. Use kg for m, 9.8 m/s² for g, and h will come out in meters.

(c)

mv₀²/2 + mgh₀ = result from part (a). You know h₀=2.00 meters. Solve for v₀ and get an answer in m/s.