A machine supplies constant power k to a mass m initially at rest. What force acts on the mass at time t?
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A machine supplies constant power k to a mass m initially at rest. What force acts on the mass at time t?

G1 Physics · Accepted Answer

Step 1 — Principle: For constant power supplied to a mass, integrate dK/dt = P. Step 2 — Working: Power P=dK/dt=k implies ½mv²=kt and v=√(2kt/m). Step 3 — Working: Since P=Fv, F=k/v=√(mk/(2t))=√(mk/2)t⁻¹ᐟ². Correct answer: A — √(mk/2) t⁻¹ᐟ².