An automobile moves at 54 km/h. A wheel has radius 0.45 m and moment of inertia 3 kg·m². If the vehicle stops uniformly in 15 s, find average braking torque on the wheel.
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An automobile moves at 54 km/h. A wheel has radius 0.45 m and moment of inertia 3 kg·m². If the vehicle stops uniformly in 15 s, find average braking torque on the wheel.

G1 Physics · Accepted Answer

Step 1: Convert speed 54 km/h=15 m/s. Step 2: Angular speed ω₀=v/R=15/0.45=100/3 rad/s. Step 3: Deceleration magnitude |α|=ω₀/15=20/9 rad/s². Step 4: Torque τ=I|α|=3×20/9=20/3≈6.67 N·m. Final answer: A — 6.66 N·m.