Power

How do you calculate power?

• P = W/t
• P = E/t
• P = w * t
• P = bbq/chicken

The SI unit for power is...?

• Watts
• Joules
• Newtons
• Meters

Is this an example of work? 
A waiter carries a tray full of meals above his head by one arm straight across the room at constant speed. 

• True
• False

A crane lifts an 8-m long steel girder weighing 2600 N up 15 m off the ground. The crane did ___ of work.

• 0 J

• 39000 J

• 20800 J

• 2600 J

Tags

NGSS.MS-PS2-4

NGSS.MS-PS3-2

Two workers use 100 N of force to move a sofa 2 meters in 2 seconds. How much power is required?

• 100 watts

• 400 watts

• 104 watts

• 50 watts

Tags

NGSS.MS-PS3-5

NGSS.MS-PS3-4

Which requires more power – a person walking up stairs or a person running up stairs?

• walking

• running

• they require equal power output

• no power is required at all

Tags

NGSS.MS-PS3-5

You move a 12-newton box up a 6-meter ramp. In order to find out how much power you created, what would you need to know?

• The mass of the box
• The slope of the ramp 
• The direction the box moved
• How long the task took

Tags

NGSS.HS-PS3-1

You do 90 joules of work in 30 seconds. How much power have you generated?

• 30 watts
• 3 watts
• 120 watts
• 270 watts

Which of the following would produce the most power?

• A mass of 10 kilograms lifted 10 meters in 10 seconds 
• A mass of 10 kilograms lifted 10 meters in 5 seconds
• A mass of 5 kilograms lifted 10 meters in 5 seconds
• A mass of 5 kilograms lifted 5 meters in 10 seconds

A mason raises a 2,000 N bag of cement from the floor to over his head (2.0 meters) in 4 seconds. What is his average power input?

• 1,000 W
• 2,000 W
• 500 W
• 100 W