Work and Mechanical Advantage

Work & Mechanical

Advantage

Open Ended

What is work?

What is Work?

• Work = using a force to move an

object a distance; when both the
force and the motion of the
object are in the same direction

Characteristics of

Work

• The object must move & involves

a transfer of energy

• Work is a measurable change in

a system, caused by a force.

• Work can be done by you, as

well as on you

Are you the pusher or the pushee?

Fill in the Blanks

A scientist delivering a speech is considered

Fill in the Blanks

A body builder lifting 400lbs above his head.

Fill in the Blanks

A mom carrying her baby from room to room

Fill in the Blanks

A student carrying her books to her locker

Fill in the Blanks

A man pushing a cart through a grocery store.

Is it Work?

• No movement = not work!

• “Carrying” = not work!

• “Holding” = not work!

Amount of Work

• The amount of work depends on 2

things:

– Size of the force
– Distance over which the force is

applied

Formula for Work :
Work = Force x Distance

Units → joule (J)

Math Response

If a man pushes a concrete block 10 meters with a force of 20N how much work has he done?

Type answer here

Correct Answer: 200

Deg^°

Rad

Math Response

A woman pushes a car 15m with a force of 5N. How much work has she done?

Type answer here

Correct Answer: 15\times5=75

Deg^°

Rad

Math Response

A woman pushes a car 15m with a force of 5N. How much work has she done?

Type answer here

Correct Answer: 15\times5=75

Deg^°

Rad

Work & Machines

• Machines make work easy (ramps,

levers, etc.)

• Apply less force to accomplish the

same task
– Ramps, levers, pulleys, etc. all

allow you to do the same amount
of work with a smaller force

Mechanical
Advantage

• Mechanical Advantage= the

number of times a machines
multiplies the effort or input force

• When a machine takes a small

input force and increases the
magnitude of the output force, a
mechanical advantage has been
produced

• Machines give us mechanical

advantage