Is Work done when there is constant velocity?

1. Oct 7, 2013

ericka141

1. The problem statement, all variables and given/known data
"You carry your 14.0 kg bag of textbooks horizontally 1.8 m above the ground, at constant velocity for a distance of 25 m. Ignore wind resistance. How much work do you do on the bag in the process?"

2. Relevant equations
W=Fd
F=ma

3. The attempt at a solution
If work equals force times distance, and force is equal to mass times acceleration, wouldn't the whole thing equal zero because of the constant velocity = no acceleration?

2. Oct 7, 2013

Staff: Mentor

The net force on the bag is zero. But what force do you exert and what work does that force do?

3. Oct 7, 2013

Enigman

W=∫F.ds
use that along with what Doc Al suggested.

4. Oct 7, 2013

ericka141

So is there only work being done in the vertical direction, aka. the force is takes you to physically hold the bag up?

5. Oct 7, 2013

Enigman

If there's displacement in that direction, yes. Work is proportional to displacement.