Question

A gramophone turntable rotating at an angular velocity of $3rad/s$ stops after one revolution. Find the angular retardation. (in $rad/s^2$)

• A. $0.698$
• B. $0.125$
  
• C. $0.569$
  
• D. $0.716$
  

Answer 1

Answer: (D)

$0.716$

Initial angular velocity ${\omega }_0=3rad/s$

It stops after one revolution means ${\omega }_t=0rad/s$ and angular displacement ${\theta }_t=2\pi rad$

Let angular retardation be $\alpha$.

${{\Rightarrow \omega }_t}^2={{\omega }_0}^2-2\alpha {\theta }_t{\Rightarrow 0}^2=3^2-2\alpha \times 2\pi \Rightarrow \alpha =0.716rad/s^2$