Power Problems

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

(Power = work / time)

• 1 minute

• 90 seconds

• 15 minutes

• 24 minutes

• 14.7 W

• 24.0 W

• 1200 kW

• 68.8 W

Power = force x (a)  

Power = ?

• work / time

• force x velocity

• force / time

• (KE + PE)²

• (mass x gravity x distance) / time

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)

• 396 J

• 40 J

• 168 J

• 224 J

Tags

NGSS.HS-PS3-2

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)

• 66 W

• 40 W

• 196 J

• 24 W

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

(W = Fd)

• 1400 J

• 28 J

• 7000 J

• 960 J

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)

• 20 W

• 32 W

• 70 W

• 960 W

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

(W = Fd)

• 4125 J

• 130 J

• 9025 J

• 960 J

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)

• 275 W

• 130 W

• 925 W

• 595 J