# Work and walk

1. Nov 30, 2015

### Baconfish

1. The problem statement, all variables and given/known data
Ok, so I have been reading all these threads where people discuss if there is any work being done while walking with a suitcase.

2. Relevant equations
So, everyone says there is no work done by walking since the suitcase is not displaced in the direction of the force by the holding arm against the gravity.

3. The attempt at a solution
But if the body starts from rest and starts walking this is an acceleration of a body(including the suitcase) which requiers a force. And this force is in the right direction... soo...

2. Nov 30, 2015

### Baconfish

Ok, so i guess the task must imply you are walking with a steady pace, so no acceleration= no force in that direction. I get it.

3. Nov 30, 2015

### Staff: Mentor

You're right! Work done in changing the speed of a body = Δ K.E.

The initial speed of the suitcase as you stoop to pick it up is zero, then it gains speed as you trudge off on your way. For most of its trip it travels at walking pace. At the destination, what is the speed of that suitcase as you release your grip on its handle?

(For the purpose of this discussion, let's assume you are the owner of the expensive suitcase and are not an airline's baggage handler. )

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