Q7 / 223 · NTA Abhyas (NEET) 2020 · Physics · Rotational Motion

By keeping moment of inertia of a body constant, if we double the time period, then angular momentum of body

A
Remains constant
Correct answer
B
Becomes half
C
Doubles
D
quadruples

Solution

Angular of the body is given by

L = I ω

or

L = I \times \frac{2 π}{T} o r L \propto \frac{1}{T}

\Rightarrow

\frac{L_{1}}{L_{2}} = \frac{T_{2}}{T_{1}}

\frac{L}{L_{2}} = \frac{2 T}{T}

(A s, T_{2} = 2 T)

So,

L_{2} = \frac{L}{2}

Thus, on doubling the time period, angular momentum of body becomes half.

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

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