A wagon was used to move a 90 lb rock 120 yds. It took 40 sec and 70 lbs of force. Can someone help me solve for efficiency and horsepower????? PLEASE :)

Answer 1

Power expended (in ft/lb/s)
= Force (lb) x Velocity (ft/s)
= 70 lb x (360 ft/40 s) = 630 ft/s
Convert this to horsepower using
550 ft-lb/s per HP. It's a bit more than 1 HP

The efficiency is zero unless the rock is being moved uphill, because all work is being done to overcome friction. The potential energy of the rock (and the wagon) remain the same

Answer 2

The ramp is 3 feet high