Physics - Rotation Question with Solution | TestHub

Initial angular speed, ${\omega }_0=\frac{600\times 2\pi }{60}=20\pi$ rad/s

Final angular speed, $\omega =\frac{1200\times 2\pi }{60}=40\pi$ rad/s

Angular acceleration, $\alpha =\frac{\omega -{\omega }_0}{t}=\frac{40\pi -20\pi }{10}=2\pi$ rad/s${}^2$

Angular displacement, $\theta ={\omega }_{0}t+\frac{1}{2}\alpha t^2$

$\theta =20\pi \times 10+\frac{1}{2}\times 2\pi \times (10{)}^2=200\pi +100\pi =300\pi$ rad

Number of revolutions, $N=\frac{\theta }{2\pi }=\frac{300\pi }{2\pi }=150$

Answer: $150$