Rotational Motion Question 80

Question: A solid cyclinder of mass 50 kg and radius 0.5 m is free to rotate about the horizontal axis. A massless string is wound round the cylinder with one end attached to it and other hanging freely. Tension in the string required to produce an angular acceleration of 2rev/s2 is

Options:

A) 25 N

B) 50 N

C) 78.5 N

D) 157 N

Show Answer

Answer:

Correct Answer: D

Solution:

  • m=50kgr=0.5α=2rev/s2

    Torque produce by the tension in the string

    =T×R=T×0.5=T2Nm …(i)

    We know τ=/α ..(ii)

    From Eqs.(i) and (ii),

    =(MR22)×(2×2π)rads2

    lsolid cylinder=MR22

    T2=50×(0.5)22×4π

    T=50×14×4π

    =50π=157N



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