Question

a body of mass 5 kg initially at rest is subjected to a force of 20 Newton how much kinetic energy is required by the body at the end of 10 second

Answer 1

Hi.

Here is the answer---

Given---
Mass = 5 kg.
Force = 20 N.
Time = 10 seconds.

Using the Formula,

  Force = Mass × Acceleration
       20 = 5 × Acceleration
 Acceleration =  4 m/s²

Using the Formula,

    $Acceleration = \frac{v - u}{t}$
                          4 = (v - 0)/10
                          v = 0.4 m/s

Using the Formula,

  Kinetic Energy = (1/2)mv²
                          = (1/2) × 5 × (0.4)²
                          = 0.4 J.


Thus, the Kinetic energy is 0.5 J.


Hope it helps.