Question 2
Work, Energy and PowerA carpenter on top of a roof 20.0 m high dropped a hammer of mass 1.5 kg and it fell freely to the ground. The kinetic energy of the hammer just before hitting the ground is [g ≈ 10 ms−2]
- A.300 J
- B.450 J
- C.600 J
- D.150 J.
Show the answer and explanation
Answer: A (300 J)
Explanation
All the potential energy becomes kinetic energy: KE = mgh = 1.5 × 10 × 20 = 300 J.