A 10 g particle moves around a circle of radius 6.4 cm from rest under constant tangential acceleration. Its kinetic energy reaches 8×10⁻⁴ J after the second revolution. Find the tangential acceleration.
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Question

A 10 g particle moves around a circle of radius 6.4 cm from rest under constant tangential acceleration. Its kinetic energy reaches 8×10⁻⁴ J after the second revolution. Find the tangential acceleration.

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G1 Physics · Accepted Answer

Step 1 — Principle: The net work on a body equals its change in kinetic energy: Wₙₑₜ = Kf − Ki. Step 2 — Working: Distance in two revolutions is s=4πR≈4π(.064)=0.804 m. Step 3 — Working: Tangential work mas equals kinetic-energy gain, so a=8×10⁻⁴/(.010×.804)≈0.10 m s⁻². Correct answer: C — 0.1 m s⁻².