| A | B |
|---|
| Force | push or pul on an object that cause it to change motion |
| heavier objects | need more force to move them |
| gravity | a force that pulls any 2 objects toward one another |
| inertia | tendency of a moving object to stay moving & a resting object to stay resting |
| Friction | a force that slows down the motion of moving objects;occurs when 2 objects rub against each other |
| Energy | he ability to do work |
| Potential energy | energy that an object has b/c of its position |
| A child sitting at the top of a slide | example of potential energy |
| Kinetic energy | the energy of motion ex. swinging downward |
| mechanical energy | kind of energy an object has b/c it can move or b/c it's moving. can be both potential & kinetic. ex. bike |
| chemical energy | enegy that comes from chemical changes. ex. gas, fuel, food, a battery |
| electrical energy | energy that comes from the flow of electricity ex. merry - go - round, radio |
| work | thge result of a force moving an object |
| 2 things must happen for work to be done | a force must act on an object & the object must move |
| Simple machines | a amchine made of 1 or 2 parts |
| inclined plane | ramp |
| wheel & axle | wheelbarrow |
| wedge | nail |
| lever | screwdriver |
| pulley | uses a rope & a wheel to pull things upward |
| screw | simple machine that hold things together |
| compund machine | a machine made up of 2 or more simple machines |
| garden shears, scissors | lever & 2 wedges |
| handmower | lever, wedges, wheel & axles |
| bike | wheels & axles, screws & levers |
| complex machine | a machine made of many simple & compound machines - usually run by fuel ot elctricity ex. car |
