Work, Efficiency, and Mechanical Advantage

Which 3 parts make up "Work"?

• A force must be applied to the object

• The object must move

• The object must move in the same direction as the force

• The object must move in the opposite direction as the force

• Distance
• Force

Which TWO of these are considered examples of "Work"?

• Pushing a box

• Walking with a backpack

• Lifting a bag of groceries

• Carrying a bag of groceries

Mathematically...we say: Work equals

• Force x Mass

• Force x Distance

• Mass x Acceleration

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• Mass (m)

• Force (F)

• Joules (J)

• Work (W)

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If it took a bulldozer 567.6 joules of work to push a mound of dirt 30.5 meters, how much force did the bulldozer have to apply?

• 18.6 N

• 0.05 N

• 18.6 J

• 17, 311.8 N

You must exert a force of 4.5 N on a book to slide it across a table. If you do 2.7 J of work in the process, how far have you moved the book?

• 0.6 J

• 12.15 m

• 0.6 m

• 1.67 m

How much work is done on a 75 N bowling ball when you carry it horizontally across a 10 m wide room?

• 750 N

• 1.34 J

• 7.5 J

• 750 J

True or False?

A simple machine does not help you do less work.

• True

• False

The output can also be known as which two?

• Load

• Resistance

• Applied Force

• Effort

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