Question

1. A football player pushes a dummy forwards at a constant 0.85m/s for 11m using 7150 J of energy. The dummy has a mass of 120 kg. Find the force the football player exerts, find the frictional force the dummy exerts.

- for my answer I got 1176N as the force the football player exerts. I don't know how to find the frictional force the dummy exerts. Is the mass necessary to find the frictional force?

2. If given the horizontal and vertical force how would the actual force be found?

Would it be the net force?

Answer 1

7150 = F * 11
so
F = 650 Newtons exerted by player
since the velocity is constant that is exactly equal and opposite to the friction force

Just use horizontal force. There is no up or down motion so vertical force does no work.

Answer 2

4n