Question

Avinash can run with a speed of 8m/s against the frictional force of 10 N ,and Kapil can move with a speed of 8m/s against the force of 25 N .who is more powerful and why

Answer 1

Kapil (
`25\; {\rm N}`,
`8\; {\rm m\cdot s^(-1)}`) produces more power, assuming that both runners are on level ground.

Step-by-step explanation:

When a force acts on a moving object, the power that this force produced would be is:

`P = F\, v`,

Where:

• 
  `F` denotes the force on the object (a vector quantity), and
• 
  `v` denotes the velocity of the object (also a vector quantity.)

In this question, it is given that both runners are at a constant speed. Hence, the forces on both runners would be balanced. The force each runner exerts would be equal in magnitude to friction, but opposite in direction:

• Force that Avinash exerts:
  `10\; {\rm N}`.
• Force that Kapil exerts:
  `25\; {\rm N}`.

The power that Avinash exerts would be:

`P = F\, v = (10\; {\rm N})\, (8\; {\rm m\cdot s^(-1)}) = 80\; {\rm W}`.

The power that Kapil exerts would be:

`P = F\, v = (25\; {\rm N})\, (8\; {\rm m\cdot s^(-1)}) = 200\; {\rm W}`.

Hence, in this motion, Kapil exerts more power.