Class 11 NEET Physics Work, Energy and Power Questions

Initial velocity u = 20 m/s; m = 1 kg
Kinetic energy = maximum potential energy
Initial kinetic energy =

1

2

×1×202=200J
mgh(max)=200J
∴h=20m
The height travelled by the body,h'=18m
∴ Loss of energy due to air friction =mgh−mgh′
⇒ Energy lost =200J−1×10×18J=20J