Question

A particle of mass 1 kg was sliding with a velocity of 10 m/s on a rough floor. It comes to rest after 5 s. Find the power at which energy is dissipated due to frictional force.

• A. 10 W
• B. 15 W
• C. 20 W
• D. 30 W

Answer 1

The correct option is A

10 W

Due to friction between floor and particle, heat would be produced and the work done by friction would be dissipated as heat.
Mass of the particle, m = 1 kg
velocity of the particle, v = 10 m/s
Time after which particle stops = 5 s

Work done by friction, W= change in kinetic energy of the body
=$\frac{1}{2}m{v}^2$
= $\frac{1}{2}\times 1\times 100=50J$

So, power at which energy is dissipated due to frictional force would be equal to the rate of work done by friction force.

$Power=\frac{workdonebyfriction}{timetaken}\frac{50}{5}=10W$