Welcome back minions!!!

Warm up on board…Place work at corner of desk up front.

Warm-up

Work A to Z

Name 26 words associated with work……Each word starts with a letter of the alphabet!

You have 4 minutes!...Go!!!!

Work!!!

• Definition of work…– Force exerted on an object that causes it to move!

• So out of the examples in the warm-up, which were actually work?

Work!!!

• Examples of work!

Work!!!

• Has to move in the direction of the force.• Has to move a distance.• No distance = no work– No matter how much force you apply!!!

“Work” or “No Work”

• 1) Work• 2) No Work

“Work” or “No Work”

• 1) Work• 2) No Work

“Work” or “No Work”

• 1) Work• 2) No Work

“Work” or “No Work”

• 1) Work• 2) No Work

“Work” or “No Work”

• 1) Work• 2) No Work

Calculating work…

• Which requires more work?– Move 100 Newton object 10 meters?– Move 10 Newton object 100 meters?– Move a 5 Newton object 200 meters?

• Work is calculated by:Work = Force x Distance

SI unit for work…

• Mid 1800’s• Physicist• James Prescott Joule• Work is Newtons x Meters = Joule (J)• Exert 1 Newton of force to move an object 1

Meter of distance = 1 Joule

Give it a try…

• 50N x 5m =250 J

• 10N x 2.5m =25J

• 100N x 300m =30,000J

Time?

• Is there a difference in work if you carry a backpack up the stairs by walking as compared to running?

No!

Work = Force x Distance(The rate at which work is done isn’t measured!)

We need more…

• What do you think of when you hear the term “Power”?

• If we factor in time with work… we are talking about POWER!!!

• Power – The rate at which work is done.– It equals the amount of work done on an object in

a unit of time.

SI unit for Power…

• Work measured in Joules• Time in seconds• Joules per second• Watt (W)– (This is used for smaller measurements)

• Kilowatt– 1000 watts

• Fact: “Horsepower”– 1 Horsepower = 746 watts

How can we figure this out?

If Work = Force x Distance

Calculating power…

• Figure this out…

Step by step…

• Power = • Power = • Power = • Power = 2,200 J/s or 2,200 W

Questions

• What is work?– 1) Rate a force is used to move an object– 2) Meters per second– 3) Exert a force on an object to move it a distance.– 4) Kilogram per cubic centimeter

Questions

• What is the SI unit for work?– 1) Horsepower– 2) Joule– 3) Watt– 4) Meter

Questions

• Equation for work– 1) Work = Force x Time– 2) – 3) Work = Time x Distance– 4) Work = Force x Distance

Questions

• What is power?– 1) Rate at which work is done– 2) Distance at which work is done– 3) Temperature at which work is done– 4) Potato

Questions

• Equation for Power– 1) – 2) – 3) Both 1 and 2– 4) None of the above

• SI unit for Power– 1) Meter– 2) Horsepower– 3) Joule– 4) Watt

Homework!!!

• Choose 5 activities at home that would be considered “work.

• Tell me individually why each is considered “work”.