Work Notes Work Formula Work Force X Distance

Work Notes

Work Formula Work = Force X Distance w = Measured in the unit Joules (J) f X Measured in the unit Newtons (N) d Measured in the unit meters (m)

Force: a push or pull Arrows are used to represent forces which show both their direction and often their strength. Balanced Force= no change in motion Net Force = 0 N Unbalanced Force= moves in the direction of the stronger force Net Force = 100 N to the left For this picture, draw the arrows and the write the force of each arrow. Then, write the information to the left of the picture. You do NOT need to draw the people playing tug of war.

work = force x distance For work to be done, the force applied must cause the object to MOVE. If the object doesn’t move (distance = 0 m), NO work is done (work = 0 J). Unbalanced Forces Force AND distance = Work Balanced Forces Force, but NO distance = NO Work 10 N Write and draw everything on this slide.

Calculating Work Example 1: Thomas pushes a box using 140 N of force and moves it 2 m. How much work does he do? W=Fxd W = 140 N x 2 m W = 280 J Work was done 140 N 2 m

Example 2: Maria uses 25 Newtons of force to pick up her dog. It travels 1. 5 meters upward. How much work did she do? W=Fxd W = 25 N x 1. 5 m W = 37. 5 J Work was done

Example 3: Jake uses 2500 N to pull the tree but it doesn’t move. How much work is he doing? W=Fxd W= 2500 N x 0 m W= 0 J NO work was done *In order to perform work, there must be a force AND a distance.

Friction: the resistance that one surface or object encounters when moving over another • Friction makes it more difficult to move an object by requiring the use of more force. Since the object is moving the same distance, more friction requires more force which means more work is being done. Smooth Surface: Wood Floor Rough Surface: Carpet Floor Draw and label the above pictures.

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 lessening the amount of force required. Ugh! Piece of cake! Less force required More force required

A ramp does not decrease the amount of work done. Since a ramp makes the work feel easier, it decreases the force required, but increases the distance traveled. No Ramp: 20 N 5 N Ramp: W= 20 J 4 m 1 m This relationship is only true when work remains constant like in this example. W= 20 J Draw and label the above pictures.

When work remains constant, force and distance are inverses (opposites). Work Force 20 J 5 N 20 J 20 N 5 to 20 is an increase Distance 4 m 1 m 4 to 1 is a decrease To keep work the same, one must increase while the other decreases. Write and draw everything shown.

Assignment Create a double bubble to compare Work vs. No Work Your bubbles can include any of the following: • Definitions • Units • Examples • Pictures • Other of your choice I will not tell you how many bubbles to have, but you need to be as detailed as possible.