Question

A cat with mass 4.0 kg jumps down to the floor from a bookcase 2.0 m high. What is the cat's change in
gravitational potential energy?

Answer 1

Answer: -7J

Explanation:

To determine the change in potential energy, use the equation ΔPE=mgΔh

Δ

PE=mg

Δ

h

, where m is the mass, g= 9.8 m/s2

g= 9.8 m/s

2

, and Δh is the change in height. Hence, we have that the potential energy PE=4.0 kg×9.8 m/s2×-2.0 m=-78 J

PE=4.0 kg

×

9.8 m/s

2

×

-2.0 m=-78 J

. To verify that this is correct, note that since the cat changes the potential energy to kinetic energy by jumping, the potential energy decreases. Hence, the potential energy should be negative.

Answer 2

Answer:

-78 J

Explanation:

I just answered that question.