MA and Simple Machines

What is effort (input) force?

• the force one exerts on a machine

• the force which an effort force must overcome in order to do work on an object via a simple machine.

• the force the machine exerts on a object

• the output work times the input distance

Using a lever, Joe is able to lift a 10,000 N car off of the ground with a force of 1000 N. What is the mechanical advantage of the lever (MA=Output Force/Input Force)?

• 1

• 10

• 100

• 1000

if a load of a lever is 100 newtons and the force you apply is 20 newtons, what is your mechanical advantage?

• 120 N
• 5 N
• 2000 N
• 80 N

Which of the following would be the correct way to report a machine's efficiency?

• 60 J

• 60

• 60%

You input 100 J of work to a machine that gives 50 J of work output. What is the machine's efficiency?

• 150%

• 50%

• 2%

• 5000%

You solve a problem and find that you have machine with 150% efficiency. Can your answer be correct?

• No, the answer is wrong.

• Yes, the answer can be right.

• Not enough information to tell.

Which is not a type of simple machine?

• spring
• screw
• pulley
• wedge

work is...

• energy from the sun
• a type of machine
• a force that moves an object
• a force that pulls you toward the earh

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

• lever
• inclined plane
• pulley
• screw

Which of these is not an example of an inclined plane?

• ladder
• stairs
• wall
• driveway