Simple machine

Which of the following does a simple machine do?

• allows people to use less force over a longer distance

• reduce减少 the amount of force needed to do work

• change the direction of the applied force外加的力

• all of the above

Which type of simple machine is this?

• Pulley

• Wheel and Axle

• Wedge

• Lever

What simple machine is this?

Why did they choose this machine?

• Lever

• Wedge

• Inclined plane

• Screw

What type of work would a pulley help a person to do?

• cut food

• record a video

• lift a heavy thing

• play music

What is the mechanical advantage?

• The More distance traveled, the more force required所需要的.

• More distance traveled, but less force required所需要的.

• A measure of when is the best time to use a simple machine

Which simple machine has the mechanical advantage机械优势 to reduce the friction of moving something?

• Lever

• Inclined Plane

• Screw

• Wheel and Axle

Answer explanation

Which simple machine has the mechanical advantage to change the direction方向 of a force?

• Wheel and Axle

• Wedge

• Pulley

• Screw

Answer explanation

Compound machines复合机械 consist of two or more simple machines combined together to make work easier.

What two simple machines are used in scissors?

• Lever and a wheel/ axle

• Screw and a wedge

• Wedge and a lever

• Pulley and a lever

Answer explanation

What three simple machines are used in a bicycle?

• Wheel/ axle, pulley, and a lever.

• Inclined plane, pulley, and wheel/ axle.

• Wedge, lever, and screw.

• Screw, lever, and Inclined plane.

Answer explanation

To increase the mechanical advantage of a lever

• make sure the fulcrum支点 is in the middle of the lever

• move the fulcrum支点 closer to the effort (people)

• move the fulcrum closer to the box

• use a bigger fulcrum支点