6.1 – Work6.1 – Work

ObjectivesObjectives

Explain the meaning of work.Explain the meaning of work. Describe how work and energy are related.Describe how work and energy are related. Calculate the work done by a given force Calculate the work done by a given force

exerted on a body.exerted on a body. Calculate power.Calculate power. Relate power to work, and solve problems Relate power to work, and solve problems

involving acceleration, force, distance and involving acceleration, force, distance and time.time.

WorkWork

Transfer of energy that occurs when Transfer of energy that occurs when a force makes an object movea force makes an object move

Work is done on an Work is done on an

object only when a object only when a

FORCE is applied to FORCE is applied to

the object and the the object and the

object movesobject moves

For work to occur, an object must For work to occur, an object must MOVE!MOVE!

The motion of the object must be in The motion of the object must be in the the same directionsame direction as the applied as the applied force on the object.force on the object.

Work & EnergyWork & Energy

RelatedRelated Energy is always transferred from Energy is always transferred from

the object DOING the work to the the object DOING the work to the object on which the work is DONE.object on which the work is DONE.

Calculating WorkCalculating Work

Work equals force times distanceWork equals force times distance Measured in JoulesMeasured in Joules

PowerPower

Amount of work Amount of work done in a certain done in a certain amount of timeamount of time

Rate at which Rate at which work is donework is done

Calculating PowerCalculating Power

Power equals work divided by timePower equals work divided by time Measured in watts (W)Measured in watts (W)

Power & EnergyPower & Energy

Since Work & Energy are related, Since Work & Energy are related, power & energy are also relatedpower & energy are also related

Power equals energy divided by timePower equals energy divided by time

In-Class AssignmentIn-Class Assignment

On a separate piece of paperOn a separate piece of paper

1.1. Describe how the scientific definition Describe how the scientific definition of work is different from the everyday of work is different from the everyday meaning of work.meaning of work.

2.2. Identify 5 forms of WORK you have Identify 5 forms of WORK you have done within the last couple daysdone within the last couple days, use , use complete sentences to describe what you complete sentences to describe what you did and the distance you moveddid and the distance you moved

– Example – This morning I lifted a case of water Example – This morning I lifted a case of water from my car and carried it 10 feet into the from my car and carried it 10 feet into the house.house.