Question

If force f = (2i+j+k) N is acting on a particle moving with constant velocity v=(i+2j+k) metre per second power delivered by force is

Answer 1

Answer:

5 watt

Explanation:

power=w/t=(f.s)/t=f.v

so take the dot product of force and velocity u will get 5

Answer 2

Well, we know that work done by a force is given by path integral of dot product of force and displacement. Now, since the body is moving with constant velocity, we could calculate the work done per second by F.v and of course, that's what we call power! Here the questioner wanted to make our life simpler hence didn't give any displacement dependent force, which would require integrals, but just a dummy constant force. And also a piece of knowledge for you....Can a particle move with constant velocity when it is under an action of force?? Think about it [Hint : is it the only force which acts on that body? Then what is the significance of work done?]