Question

A particle performing $UCM$ changes its angular velocity from $70$ r.p.m to $130$ r.p.m in $18s$. Find the angular acceleration of the particle. (in $rad/s^2$)

• A. $0.36$
  
• B. $0.349$
  
• C. $0.69$
  
• D. $0.48$
  

Answer 1

Answer: (B)

$0.349$

Initial angular velocity ${\omega }_0=70\times \frac{2\pi }{60sec}=\frac{7}{3}\pi rad/s$

Final angular velocity ${\omega }_t=130\times \frac{2\pi }{60sec}=\frac{13}{3}\pi rad/s$

As we know, ${\omega }_t={\omega }_0+\alpha t$

$\Rightarrow \alpha =\frac{{\omega }_t-{\omega }_0}{t}=\frac{\frac{13}{3}\pi -\frac{7}{3}\pi }{18}=0.349rad/s^2$