Q102 / 180 · NEET 2015 (Phase 2) · Physics

An automobile moves on a road with a speed of 54 km h-1 . The radius of its wheels is 0.45 m and the moment of inertia of the wheel about its axis of rotation is 3 kg m2 . If the vehicle is brought to rest in 15 s , the magnitude of average torque transmitted by its brakes to the wheel is:

  • A
    8.58 kg m2 s-2
  • B
    10.86 kg m2 s-2
  • C
    2.86 kg m2 s-2
  • Correct answer
    D
    6.66 kg m2 s-2

Solution

ωi=150.45=1003 ωf=0

ωf=ωi+αt

0=1003+-α(15)

α=10045

τ=Iα=3×10045=6.66 N m

Hence, the correct answer is option: 'D'.

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