NTA Abhyas JEE Main2020PhysicsWork, Power and EnergyPractice
A bucket full of water weighs 5 kg , it is pulled from a well 20 m deep. There is a small hole in the bucket through which water leaks at a constant rate. If it is observed that for every metre the bucket loses 0 .2 kg mass of water, then the total work done in pulling the bucket up from the well is [ g = 10 m s - 2 ]
Options
- A600 J
- B400 J
- C100 J
- D500 J
Correct answer
A. 600 J
Step-by-step solution
The weight of bucket when it has been pulled up a distance x i s (5-0.2 x ) . Hence, the required work is W = ∫ x = 20 x = 0 - 5 - 0.2 x × 10 × d x = 50 x x = 0 x = 20 - 2 x 2 2 x = 0 x = 20 W = 50 × 20 - 20 2 = 600 J