Q32 / 223 · NTA Abhyas (NEET) 2020 · Physics · Rotational Motion

A disc has mass $M$ and radius $R$ . How much tangential force should be applied to the rim of the disc so as to rotate the disc with angular velocity $ω$ in time $t$ ?

A
$\frac{M R ω}{4 t}$
Correct answer
B
$\frac{M R ω}{2 t}$
C
$\frac{M R ω}{t}$
D
$M R ω t$

Solution

τ = I α

F \times R = \frac{M R^{2}}{2} \times \frac{ω}{t}

F = \frac{M R}{2} \times \frac{ω}{t}

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

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