Physicsmedium · Past Paper
A stone of mass 2 kg is dropped from a tower 20 m high. What is its kinetic energy just before hitting the ground?
A40 J
B200 J
C400 J
D800 J
✓ Correct Answer: C — 400 J
By conservation of energy, KE at bottom = PE at top = mgh = 2 * 10 * 20 = 400 J.
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