Forces/Motion

Force A push or a pull

Speed The distance an object moves in a given amount of time.

Motion A change in the position of an object as it is moving

Gravity A force that attracts objects to each other. The force of gravity holds you to Earth Gravity is a PULLING force

Work The measure of force it takes to move an object a certain distance.

Weight A measure of the pull of gravity on an object.

Magnet An object that pulls objects made from iron toward it

Friction A force that slows down a moving object when it rubs against another object

Lever A simple machine that helps move things with less force. (hammer)

Wedge A simple machine used to cut or split things. (ax)

Wheel and Axle A simple machine used to move things more easily. (bicycle)

Screw A simple machine used to hold things together. (screw)

Inclined Plane A simple machine that is a flat surface with one end higher than the other. (ramp)

Pulley A simple machine used to lift things. (flag)

So let’s review… 1. A push or pull is a _________ force 2. The distance an object moves in a certain amount of time is ___________. speed 3. A change in position is called ______ motion 4. A force that slows down a moving object and sometimes creates heat is ________. friction

5. The pulling force that keeps us on Earth is ______________. gravity 6. The measure of the pull of gravity is __. weight 7. The measure of force it takes to move an object is _______________. work

Let’s review Simple Machines An example of a lever would be… A hammer An example of a pulley is a… Flagpole A wheel and axle is… A bicycle

An example of a screw is… A screw An example of an inclined plane is a… Ramp An example of a wedge is… An ax