Question

A 1.47-newton baseball is dropped from a height of 10.0 meters and falls through the air to the ground. The kinetic energy of the ball is 12.0 joules the instant before the ball strikes the ground. The maximum amount of mechanical energy converted to internal energy during the fall is_________.

Answer 1

Answer:

The maximum amount of mechanical energy converted to internal energy during the fall is 26.7 joules

Explanation:

Potential Energy (PE) = weight of baseball × height = 1.47N × 10m = 14.7Nm = 14.7 joules

Kinetic Energy (KE) = 12 joules

Maximum amount of mechanical energy converted to internal energy during the fall = PE + KE = 14.7 joules + 12 joules = 26.7 joules

Answer 2

Answer:

ΔEinternal = - 2.7 J

Explanation:

Given

W = m*g = 1.47 N

hinitial = 10.0 m

Kfinal = 12.0 J

We can apply

ΔE = ΔEinternal

then

ΔE = (Kfinal + Ufinal) - (Kinitial + Uinitial)

⇒   ΔE = (Kfinal + 0 J) - (0 J + Uinitial) = Kfinal - Uinitial

⇒   ΔE = Kfinal - (W*hfinal) = 12 J  - (1.47 N*10.0 m)

⇒   ΔE = 12 J - 14.7 J = - 2.7 J

then

ΔEinternal = - 2.7 J