A constant force of 20 N acts on a 5 kg body initially at rest. Its speed after 3 s is:
A60 m s⁻¹
B15 m s⁻¹
C4 m s⁻¹
D12 m s⁻¹
Answer & Solution
Correct answer: D. 12 m s⁻¹
a = F/m = 20/5 = 4 m s⁻²; then v = u + at = 0 + 4×3 = 12 m s⁻¹.
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