Power Problems

How long will it take a 20 W motor to do 1200 J of work?

(Power = work / time)

Margo lifts a 3 kg book from the bottom shelf to the top shelf of a bookcase, a distance of 2 meters. If it takes Margo 4 seconds to move the book, what was her power output?

$$power\ =\ \frac{mgd}{t}$$

Power = force x (a)  

Power = ?

A steel bar with a normal force of 22 N is lifted by a construction crane to a height of 18 meters. How much work was done by the crane?

(work = Fd)

A steel bar with a normal force of 22 N is lifted by a construction crane. It took the crane 6 seconds to lift the bar to a height of 18 meters. What was the power output of the crane?

(Power = work / time)

Ted uses 40 N of force to push a box 35 meters down the hallway. How much work did Ted do?

(W = Fd)

Ted uses 40 N of force to push a box 35 meters down the hallway in 7 seconds. What was Ted's power output?

(P = W / t)

Arleth uses 75 N of force to pull a wagon down a 55 m sidewalk. How much work did she do?

(W = Fd)

Arleth uses 75 N of force to pull a wagon down a 55 m sidewalk. If she does this in 15 seconds, what was her power output?

(Power = Work / time)