Q89 / 90 · JEE Main 2021 (20 Jul Shift 2) · Physics

A body rotating with an angular speed of $600 rpm$ is uniformly accelerated to $1800 rpm$ in $10 \sec .$ The number of rotations made in the process is

Correct answer: 200

Solution

$ω_{f} = ω_{0} + α t$

$α = 1200 \times 6$

$θ = ω_{0} t + \frac{1}{2} α t^{2}$

$= 600 \times \frac{10}{60} + \frac{1}{2} \times 1200 \times 6 \times \frac{1}{36}$

$θ = 200$

Hence, the correct answer is 200.

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