Mechanical Systems Review

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

The Pulley shown has a mechanical advantage of 4. However, due to friction, this is not the case. 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

No machine in existence has 100% efficiency due to ____________________.

• magic
• friction
• smoke
• input

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