POE Simple Machines

Mechanical Advantage (MA) is:

• Ratio of the magnitude of the resistance and effort forces
• Ratio of distance traveled by the effort and the resistance force
• All of the above
• None of the above

If MA is greater than 1:

• Proportionally less effort force is required to overcome the resistance force
• Proportionally greater effort force is required to overcome the resistance force
• Proportionally less effort distance is required to overcome the resistance force
• MA cannot be greater than 1

Which simple machine will have a mechanical advantage less than 1?

• crane
• weight machine
• a windmill
• a conveyer belt

An inclined plane is 15 meters long and raises 3 meter high.  If you want to push a 20 N box up the inclined plane, how much effort force will you need? Remember, FeDe = FrDr

•  900 N
• 4 N
• 2.25 N
•   100 N

A pulley brings a 100 kg piano up into a second story window.  What is the ideal mechanical advantage if the pulley has 5 strands?

• 20
• 500
• 5
• 0.05

Tommy and Jimmy are on a seesaw like the picture.  Tommy weighs 40 lb and Jimmy weighs 30 lb.  What is the Mechanical Advantage when Jimmy makes the two boys level?

• 1.3
• 0.75
• 1
• 120

The stairs leading up a lighthouse are shaped like a screw.  If  the pitch of the stairway was 1/0.005 and the radius of the stairway was 3ft,  how much is the ideal mechanical advantage? Remember IMA = (2piR)/pitch

• 1.0
• 0.015
• 0.04
• 0.09

A wheelbarrow is carrying 50 lb of cement.  The radius of the wheel is 10 inches and the radius of the axel is 4 inches.  What effort force is needed to move the cement if the axle is driving the wheel?  Remember FeDe = FrDr

• 12.5 lb
• 125 lb
• 4 lb
• 20 lb

Mrs. Cruz wants to lift a bag of chocolates in a crane vending machine.  The chocolate weighs 2 lb.  When she pulled the crane with her force sensor, she saw that she put in 1.5 lb of force effort.  What is the mechanical advantage of the crane?

• 1.33
• 0.75
• 2
• 1.5

David wants to lift Moses using a moveable pulley.  If Moses weighs 150 lbs, and David uses a force of 30 lbs, how much is the mechanical advantage?

• 10
• 450
• 5
• 8