How much power is required to raise a 100 kg crate a vertical distance of 2 m in a time of 4 s? a. 200 w b. 500 w c. 800 w d. 2000 w

Power = (work done) / (time to do the work)

Work done = (force) x (distance)

Force = (weight of the crate) = (mass of the crate) x (gravity)

Crate weight = (100 kg) x (9.8 m/s²)

Force = 980 Newtons

Work done = (980 N) x (2 m) = 1,960 Joules

Power = (1,960 Joules) / (4 seconds)

Power = 490 Joules per second

(Whoever wrote the question used 10 m/s² for gravity instead of 9.8 m/s², so his answer came out to be 500 W.  That's choice-B .)

Power = 490 watts