Question

A force $F=10\text{N}$ is acting on pulley of mass $M=2\text{kg}$ and radius $R=1\text{m}$ as shown in the figure. If pulley is rotating with constant angular velocity $\omega =4\text{rad/s}$. Find the power delivered by the force $F$ to the pulley.

• A. $20\text{J/s}$
• B. $10\text{J/s}$
• C. $30\text{J/s}$
• D. $40\text{J/s}$

Answer 1

The correct option is D $40\text{J/s}$


As we know that torque about COM of pulley due to force $F$ is given by,
$\tau =R\times F=(1\times 10)=10\text{N-m}$

$\therefore$ Power delivered by torque $\tau$ is given by
$P=\tau \omega =(10\times 4)\text{J/s}=40\text{J/s}$