In which of the following cases would you do the least amount of work? Choose on

Question

In which of the following cases would you do the least amount of work?
Choose one answer.
1. You push a box a distance d across a floor.
2. You pick up the box, walk a distance d, and gently put the box down on the floor.
3. You pick up the box, walk a distance d, and drop the box.
4. Both 1 and 2 are the least.
5. Both 1 and 3 are the least.
6. Both 2 and 3 are the least.
7. The amount of work done is the same in all three cases.
8. The amount of work cannot be determined from information given.

I am a little confused with this question, can you please break down the reasoning?

Thanks

Explanation / Answer

Note, Two Cases:

If the floor is frictionless
Then pushing causes zero work. And lifting and walking ways also requires zero work. as gravity is conservative force..

But if the floor is not frictionless. then only sliding causes work.

 

BUT in BOTH cases, the lifting and going to destination and putting it gently  requires zero work. !!!!

 

If we just drop it, then we  give the box some Kinetic energy :)

So  (2 ) is  correct

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