Levers, Wheel and Axle, Pulley

The boy can lift the barrel or roll the barrel up the inclined plane.  In which does he do more work?

• when lifting the barrel
• when rolling the barrel
• neither- both are the same amount
• neither- no work is done

Which is a first class lever?

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• 
• 

Which is a third class lever?

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• 
• 

What class lever does this image best represent?

• First

• Second

• Third

• All classes

What is the ideal mechanical advantage for this block and tackle pulley system?

• 2

• 5

• 1

• 4

What is the actual mechanical advantage if the resistance force is 50 lbs and

the effort force is 15 lbs?

• 0.3

• 3.33

• 35

• 3.33 lbs

The load is 3 feet from the pivot point, the effort is applied 12 feet from the pivot point and the load weights 30 pounds. What is the mechanical advantage?

• 4

• 3

• 12

• 34

The load is 3 feet from the pivot point, the effort is applied 12 feet from the pivot point and the load weights 50 pounds. What is the effort required to lift that 50 pound load?

• 150 lbs

• 12.5 lbs

• 36

• 24

Which one describes a first class lever? (including the MA)

• Fulcrum between effort and resistance; M.A. is equal to, less than 1, or greater than 1.

• Resistance between effort and fulcrum; M.A. is greater than 1

• Effort is between resistance and fulcrum; M.A. is less than 1

What is the formula to find % efficiency?

• (AMA/IMA)

• (AMA/IMA) X 100

• AMA X IMA X 100

• (IMA/AMA) X 100