alleryA net force F = 6t newton (t in seconds) acts on a 2 kg body initially at rest. The speed of the body at t = 4 s is:
A48 m s⁻¹
B6 m s⁻¹
C24 m s⁻¹
D12 m s⁻¹
Answer & Solution
Correct answer: C. 24 m s⁻¹
Impulse = ∫₀⁴ 6t dt = 3t²|₀⁴ = 48 N s = Δp
hence v = Δp/m = 48/2 = 24 m s⁻¹.
Distractors drop the time-integration or the mass.
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