Question
Question: The mass of a bucket containing water is 10 kg. What is the work done in pulling up the bucket from ...
The mass of a bucket containing water is 10 kg. What is the work done in pulling up the bucket from a well of depth 10 m if water is pouring out at a uniform rate from a hole in it and there is loss of 2kg of water from it while it reaches the top 
A
1000 J
B
800 J
C
900 J
D
500 J
Answer
900 J
Explanation
Solution
Gravitational force on bucket at starting position
= mg = 10 × 10 = 100 N
Gravitational force on bucket at final position
= 8 × 10 = 80 N
So the average force through out the vertical motion
∴ Work done = Force × displacement = 90 × 10 = 900 J.