Simple machines and work

Which of the following is work according to the scientific definition?

• pushing a box across the floor
• standing still while holding something heavy
• walking with a backpack on
• all of these are considered "work"

What unit is used to measure work?

• Joule
• Meter
• Newton
• Gram

Simple machines make work easier by 

• increasing the energy needed to do the work, while reducing friction.
• changing the size or direction of the force, or both
• reducing work
• simple machines do all of these

Which pulley makes work easiest?

• 1
• 2
• 3
• they are all the same

Is this person doing work?

• YES
• NO

Identify this simple machine

• Lever
• Wheel & Axle
• Inclined Plane
• Screw

Two examples of a pulley...

• knife & axe blade
• lightbulb & screw
• flagpole hoist & window blinds
• catapult & teeter totter

An inclined plane wrapped around a rod forms this simple machine 

• lever
• pulley
• screw
• wedge 

A simple machine that consists a rigid bar that pivot about a fixed point

• lever
• pulley
• wheel and axle
• fulcrum 

A seesaw is an example of a  

• wedge
• lever 
• inclined plane 
• pulley