Question

A particle moves along a circular path of length $15cm$ with a constant angular acceleration of $4rad/s^2$. If the initial angular speed of the particle is $5rad/s$, find the angular displacement of the particle in $5s$. (in rad)

• A. $70$
  
• B. $20$
  
• C. $75$
  
• D. $82$
  

Answer 1

The correct option is C $75$

Angular displacement equation is given by

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

Given that ${\omega }_0=5rad/s$, $\alpha =4rad/s^2$ and $t=5sec$

$\Rightarrow {\theta }_t=5\times 5+\frac{1}{2}\times 4\times 5^2\Rightarrow {\theta }_t=75rad$