Watts and Kilowatts

Power & Watts

Essential Questions

1. How can the conservation of energy theorem be related to work done over time?

2. How can power be calculated?

Multiple Choice

Which of these is a measure of force?

• 100 newtons
• 100 meters per second
• 100 joules
• 100 watts

Multiple Choice

A weightlifter lifts two 300 newton weights 1.5 meters off the ground. How much work has he done?

• 600 J 
• 660 J
• 900 J 
• 1200 J 

Multiple Choice

A kid applies a force of 70 N to a ball over 1.1 meters. How much work did he do on the ball? 

• 77 J
• 7.7 J 
• 0.7 J 
• 770 J 

Open Ended

What's your good thing for today OR what do you want to be when you're grown up?

Multiple Choice

A steam engine does 50 J of work in 12 s. What is

the power supplied by the engine?

• 1.1 W

• 2.3 W

• 2.8 W

• 4.2 W

Multiple Choice

How long must a 350 W engine run in order to

produce 720 kJ of work? (Remember a kJ = 1000 J)

• 1,230 s

• 1,450 s

• 1,820 s

• 2,060 s

Multiple Choice

How long must a 350 W engine run in order to

produce 360 kJ of work?

• 681 s

• 804 s

• 1,030 s

• 1,440 s

Multiple Choice

A 12 kW motor runs a vehicle at a speed of 8.0 m/s.

What is the force supplied by the engine? (Remember 1 kW = 1000 W)

• 800 N

• 1000 N

• 1300 N

• 1500 N

Multiple Choice

A 24 kW motor runs a vehicle at a speed of 8 m/s.

What is the force supplied by the engine?

• 1,100 N

• 1,200 N

• 1,500 N

• 3,000 N