A boy of mass 30 kg jumps off a low wall with negligible initial velocity. After 1 second of free fall, his velocity is approximately (g = 10 m/s²):
A0 (free fall)
B10 m/s downward
C30 m/s downward
D100 m/s downward
Answer & Solution
Correct answer: B. 10 m/s downward
In free fall, acceleration = g = 10 m/s² downward. Starting from rest (u = 0), after t = 1 s: v = u + gt = 0 + 10 × 1 = 10 m/s downward. Note: the answer doesn't depend on the boy's mass — all bodies in free fall accelerate at the same rate.
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