A horizontal force of 300.0 N is used to push a 145-kg mass 30.0 m horizontally in 3.00 s.
(A) Calculate the work done on the mass.
(B) Calculate the power developed.

Work = (force) x (distance)Work = (300 N) x (30 m) = 9,000 joulesPower = (work) / (time)Power = (9,000 joules) / (3 sec) = 3,000 wattsOops.  I didn't use the mass of the 145-kg object. Probably because I didn't need it.