Question

A body rotating with uniform angular acceleration covers $100\pi \left(radian\right)$ in the first $5s$ after the start. Its angular speed at the end of $5s$ (in radian/s) is then

• A. $40\pi$
• B. $30\pi$
• C. $20\pi$
• D. $10\pi$

Answer 1

The correct option is C $20\pi$

$\theta =150rod,t=5\sec$

$w_i=0rad{s}^{-1}$

$\theta =W_{i}t+\frac{1}{2}\times \propto \times t^2$

$\propto =8rad{s}^{-2}$

$w_f=w_i+\propto t$

$=8\times 5$

$=40rad{s}^{-1}$