Initially, four identical uniform blocks, each of mass 'm' and thickness 'h' are spread on a table. How much work is done on the hook in stacking them on top of one another?
Correct answer: D. 6mgh
- A. 2mgh
- B. 3mgh
- C. 4mgh
- D. 6mgh
Explanation
W=mg(0h)+mg(1h)+mg(2h)+mg(3h) = 0+mgh+2mgh+3mgh= 6mgh
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Work and Energy
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Work and Energy questions
A truck and a car are moving with equal velocity. On applying brakes, both will stop after a certain distance, then?
If force and displacement of a particle in direction of force are doubled. Work would be
A man of weight 500 newtons walks up to the top of a building of height of 20 m above the street level. The increase in the potential energy of man is
Output of a truck is 4500 J and its efficiency is 50%, input energy provided to truck is:
A pump motor is used to deliver water at a certain rate from a given pipe. To obtain thrice as much water from the same pipe in the same time, power of the motor has been increased:
A bomb of mass 12kg at rest explodes into two pieces of masses 4 kg and 8 kg, the velocity of mass 8kg is 5 m/s. the kinetic energy of mass 4 kg is: