Work and Power

Hello! You Need: You Need: Pencil Pencil Science Notebook Science Notebook Science Folder Science Folder Calculator Calculator Drawing from Fri Drawing from Fri Everything else goes into the corners of the room. Everything else goes into the corners of the room. Bell Work: Open your science notebook to a new page. Title the page “Work.” Answer the question below. As a student your teacher expect you to go home and do homework. Are you really doing work? Why or Why not?

To Do Work: You Need 2 Things A Force – A push or a pull on something. A Force – A push or a pull on something. Push a chair Push a chair Pull your notebook off a desk. Pull your notebook off a desk. Other examples? Other examples? Motion – Movement Measured in miles Kilometers Meters Other examples?

Force is necessary to do work. Work: The use of force to move an object some distance. Work: The use of force to move an object some distance. In order for work to happen, we have to have the following: In order for work to happen, we have to have the following: Force Force Motion Motion Motion in the direction of the force Motion in the direction of the force If one of those three things is not present, then no work is being done. If one of those three things is not present, then no work is being done.

Bell Work Answer You are doing homework. Is there force? Is there motion? Is the movement in the direction of the force? You are doing homework. Is there force? Is there motion? Is the movement in the direction of the force? Discuss with a neighbor if doing your homework is actually “Work.” Discuss with a neighbor if doing your homework is actually “Work.”

Rotating Lab Stations Label your paper 1-4, skipping two lines in between numbers. Label your paper 1-4, skipping two lines in between numbers. Go to your assigned lab station. You need your notebook and a pencil. Go to your assigned lab station. You need your notebook and a pencil. With your group, decide if the picture on your station is doing work. With your group, decide if the picture on your station is doing work. If it is doing work explain, why? If it is not doing work, explain what characteristic is missing. If it is doing work explain, why? If it is not doing work, explain what characteristic is missing. You will be moving around to all 4 lab tables. You will be moving around to all 4 lab tables.

Number 1 – Picking a chair up and walking forward Force Motion

Number 2 – Mr. Feeny at his office

Number 3 – Picking a weight up above your head Force Motion

Number 4 – Pushing a lawnmower. Force Motion

Calculating Work Work is a measure of how much force is applied over a certain distance. Work is a measure of how much force is applied over a certain distance. The formula for finding the amount of work done is below: The formula for finding the amount of work done is below: W= Force x Distance W=FxD

Other Equations W FDFD Work = Force x Distance Force = Work / Distance Distance = Work / Force

Units The formula for work is W=FxD The formula for work is W=FxD What is being measured?Unit ForceNewton (N) DistanceMeter (M) WorkNewton x Meter or Joule (J)

Calculations Practice W? W? F = 10 N F = 10 N D = 5 M D = 5 M W=FxD W=FxD W= 10N x 5M W= 10N x 5M W= 10 x 5 W= 10 x 5 W= 50 J W= 50 J

Calculations Practice W? W? F = 12N F = 12N D = 9M D = 9M W=FxD W=FxD W=12N x 9M W=12N x 9M W= 12 x 9 W= 12 x 9 W= 108 J W= 108 J

Calculations Practice W18 J W18 J F = ? F = ? D = 3M D = 3M Force = Work/Distance Force = Work/Distance Force = 18 J / 3 M Force = 18 J / 3 M F= 18/3 F= 18/3 F= 6N F= 6N

Review A body builder lifts 350 pounds above his head. Is any work done? A body builder lifts 350 pounds above his head. Is any work done? A. Yes A. Yes B. No B. No

Review A body builder lifts 350 pounds above his head. Is any work done? A body builder lifts 350 pounds above his head. Is any work done? A. Yes A. Yes

Review A scientist delivers a speech to an audience of his peers. Is work done? A scientist delivers a speech to an audience of his peers. Is work done? A. Yes A. Yes B. No B. No

Review A scientist delivers a speech to an audience of his peers. Is work done? A scientist delivers a speech to an audience of his peers. Is work done? B. No B. No

Review If a man pushes a concrete block 10 meters with a force of 20 N, how much work has he done? If a man pushes a concrete block 10 meters with a force of 20 N, how much work has he done? A. 200 N A. 200 N B. 150 J B. 150 J C. 200 J C. 200 J D. 150 N D. 150 N

Review If a man pushes a concrete block 10 meters with a force of 20 N, how much work has he done? If a man pushes a concrete block 10 meters with a force of 20 N, how much work has he done? C. 200 J C. 200 J