Question

a boy of mass 40 kg is running down from third floor of a building which is at a height of 16 metre to the first floor which at a height of 8 metre calculate the change in potential energy and the speed at which he is running​

Answer 1

Answer: taking g = 10 m/s^2

Change is PE = 3200 J

Speed = 12.65 m/s

Step-by-step explanation:

PE = mgh

Change in PE = m . g . change in h

                        = 40 x 10 x 8

                        = 3200 J

Velocity :

change in KE = Change in PE

3200 = 0.5 x 40 x v^2

v = 12.65 ms^-1