A 3 kg body experiences a constant force and its displacement follows s=t²/3 (metres), with t in seconds. Find work done in the first 2 s.
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A 3 kg body experiences a constant force and its displacement follows s=t²/3 (metres), with t in seconds. Find work done in the first 2 s.

G1 Physics · Accepted Answer

Step 1 — Principle: For a position-dependent force, calculate work by integrating force along displacement: W = ∫F dx. Step 2 — Working: From s=t²/3, a=d²s/dt²=2/3 m s⁻². Step 3 — Working: F=ma=3×2/3=2 N. Step 4 — Working: In 2 s, s=4/3 m, so W=Fs=2×4/3=8/3 J. Correct answer: D — 8/3 J.