Work, Energy And Power For Rotating Body MCQ - Practice Questions with Answers

1. Work-

For translation motion

$$
W=\int F d s
$$

So for rotational motion

$$
W=\int \tau d \theta
$$
 

2. Rotational kinetic energy-

The energy a body has by virtue of its rotational motion is called its rotational kinetic energy.

3. Power =Rate of change of kinetic energy  

For translation motion $P=\vec{F} \cdot \vec{V} P=\vec{F} \cdot \vec{V}$
So for rotational motion

$$
P=\frac{d\left(K_R\right)}{d t}=\frac{d\left(\frac{1}{2} I \omega^2\right)}{d t}=I \omega \frac{d \omega}{d t}=I \alpha \omega=\tau \cdot \omega
$$

Or $P=\vec{\tau} \cdot \vec{\omega}$