Question

A wheel is making revolutions about its axis with uniform angular acceleration. Starting from rest, it reaches 100 rev/sec in 4 seconds. Find the angular acceleration.

• A. $50\frac{rev}{s^2}$
• B. $25\frac{rev}{s^2}$
• C. $40\frac{rev}{s^2}$
• D. $500\pi \frac{radians}{s^2}$

Answer 1

The correct option is B

$25\frac{rev}{s^2}$

Initial angular velocity = ${\omega }_0$ = 0

Angular velocity after 4 seconds = $\omega$ = $100$$\frac{rev}{s}$

= $100\times 2\pi \frac{rad}{s}$

We know,

$\omega$ = $100$ $\frac{rev}{s}$ = $0+\alpha \times t$

$200\pi$ = $4\alpha$

$\alpha$ = $50\pi \frac{rad}{s^2}$ or $\alpha$ = $25\frac{revolutions}{s^2}$