Work, Power, and Machines

if you push a cart with a force of 60 N for 2 m... how much work have you done

• 120 J

• 30 J

• 120 N

• 30 N

Which situation is work not done?

• lifting a 20 pound box off the floor
• holding a 20 pound box above the floor
• sliding a 20 pound box across the floor
• sliding a 20 pound box up an inclined plane

A machine with a 5-N input force and a 25-N output force has a mechanical advantage of?

• 2

• 5

• 20

• 125

The correct unit to measure power is..

• Joule

• Newton

• Watt

• Pascal

In which case is work being done:

• a student sleeps

• a student carries his chair across the room

• a student pushes a locked door that doesn't move

• a student picks up his chair

Tags

NGSS.MS-PS3-5

If you use a crowbar to get a lid off a bucket, which simple machine are your using?

• inclined plane

• wheel and axle

• pulley

• lever

What type of simple machine is found on the lid of a pickle jar?

• lever

• screw

• pulley

• wedge

A flagpole or blinds on a window would be an example of which simple machine:

• pulley

• wedge

• inclined plane

• screw

No machine can be 100 % efficient because of

• waste energy

• thermal energy

• convetion energy

• friction

Which of these would show the most power

• picking up a light object in a long amount of time

• holding a heavy object for a long time

• picking up a heavy object in a short amount of time

• picking up a light object in a short amount of time

Tags

NGSS.MS-PS3-5