-
A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (g = 10 m/s2)
-
- 30 J
- 40 J
- 10 J
- 20 J
Correct Option: D
When the body is thrown upwards. its K.E is converted into P.E. The loss of energy due to air friction is the difference of K.E and P.E.
| mv2 - mgh = | × 1 × 400 - 1 × 18 × 10 = 200 – 180 = 20 J | |||
| 2 | 2 |
