Question

A particle is acted upon by a constant power. Then, which of the following physical quantity remains same?

• A. Speed
• B. Rate of change of acceleration
• C. Kinetic energy
• D. Rate of change of kinetic energy

Answer 1

Answer: (D)

Rate of change of kinetic energy

We know that rate of doing work is defined as power.

And by Work energy theorem work done is change in kinetic energy i.e. $W=\Delta K.E$.

So, we can write power $P=\frac{dW}{dt}$ $=\frac{d}{dt}\Delta K.E=\frac{d}{dt}\frac{m{v}^2}{2}$.

So, it is rate of change of kinetic energy.