MONDAY 16 MAY 2016 AGENDA: OPENING: NEW UNIT….. TEST GRADES POSTED SOON **work video WORKTIME: WORK NOTES CLOSING: WORK FORMULA EXAMPLES (INCLINED PLANE) WRAP UP: EXTRA CREDIT DUE! 14 DAYS??? DateEntryPage 5.16 UNIT 6.2 SPM (LAST ONE!!!!!) WORK NOTES WORK V. NO WORK DOUBLE BUBBLE 120 SC.7.A Contrast situations where work is done with different amounts of force to situations where no work is done such as moving a box with a ramp and without a ramp, or standing still SC.7.A Contrast situations where work is done with different amounts of force to situations where no work is done such as moving a box with a ramp and without a ramp, or standing still.

Work Notes !

FORCE What’s happening to this bobsled? You’d probably say that it’s being pushed forward. What’s happening to this dogsled? It’s definitely being pulled along. Read this page, but you do not need to write any of it in your notes

Force Definition A force is a push or pull. Examples of force: Gravity Magnetism Friction Weight

Examples of force Maybe a monkey is having to pull on a coke can to keep it from crashing to the floor. Is the AC/heater blowing? If so, tiny air molecules are bumping into things, trying to push them around. Many of you are pushing with your pencils to write. In fact, there are many body processes controlled by muscles pushing in your body (breathing, moving blood, digesting food, pulling your bones). At least one person is pushing with jaw muscles on gum. Read this page, but you do not need to write any of it in your notes

More force examples. If we get picky, we can consider minor things like the weight of earrings pulling on earlobes. Every time one of the millions of bacteria in the room land on something, they give it a tiny little push. Your bottom is pushing on your seat and your feet are pushing on the floor. The seat and floor, in return, are pushing right back on your body, holding you up. Read this page, but you do not need to write any of it in your notes

Units to measure force Forces come in different amounts. We measure forces using the unit “newton.” Newton is abbreviated with a capital N. 5 newtons = 5 N You’d much rather be punched by your little sister than this guy!

So, summarizing “force” A force is a push or a pull. We measure force using the unit “newton” (N). We often use arrows to represent forces…both their direction and often their strength.

Real-life application of force Draw this picture. Then, examine the forces acting on the ball. Weight of ball 7 N

But we know that the ball doesn’t actually move down? So there must be a force counter-acting the down force of the weight of the ball…that force is the ground pushing back up! Weight of ball 7 N Ground strength 7N Add the extra detail, shown here, to your picture.

So, the forces are balanced? Yes. And Newton would say that balanced forces will result in no change of motion for the object. Breezy air 2N Balanced by friction 2N To get the ball rolling, you’ll need to apply a force that is too strong to be balanced by friction. In order to get the ball to move, work must be done.

Work Definition Work is done when a force moves an object a distance in the direction of the force.

Force AND distance = WorkForce, but NO distance = NO Work Draw a t-chart and include this information Unbalanced Forces Balanced Forces

Work Units and Formula Work is measured in Joules, abbreviated J. To calculate work, use this math formula: Work (J) = Force (N) x distance (m) (W = F X D) As long as the force is in newtons and the distance is in meters, the amount of work done is measured in joules.

Work Calculation Ex. 1 J.J. pulls with 140 N of force on a bulldozer, and moves it 2 m. How much work does he do? W = F x d W = 140 N x 2 m W = 280 J

Maria picks up her 25 N chihuahua to give it a hug. It travels 1.5 meters upward. How much work did she do? W = F x d W = 25 N x 1.5 m W = 37.5 J Work Calculation Ex. 2

Tony uses 2500 N to pull the tree but it doesn’t move. How much work is Tony doing? W = F x d W= 2500 N x 0 m W= 0 J NO Work Calculation But Tony tried really hard! Why did he not do any work? ***In order to perform work, there must be a force AND a distance.

Read and answer this to yourself. (This does not need to be written in your notes.)

Ramp vs. No Ramp There’s a hard way and an easy way to do most anything. Simple machines, such as a ramp, are devices that take advantage of making the same amount of work at least FEEL easier. AKA: Ramps don’t change the amount of work, but they do make it easier by lowering the amount of force. Ugh! Piece of cake!

On the next clean page in your notebook: Create a double bubble to compare AND contrast Work vs. No Work. (Have Work on one side and No Work on the other side) I will not tell you how many bubbles to have, but you need to be as detailed as possible. Work vs. No Work Double Bubble