Newton’s Laws of Motion Vocabulary 1. force – a push or pull exerted by one object on another, causing a change in motion 2. inertia – the tendency of a moving object to keep moving in a straight line or of any object to resist a change in motion 3. friction – a force that opposes the motion of one object moving past another 4. energy – an object’s ability to do work 5. potential energy – the stored energy of position possessed by an object 6. kinetic energy – the energy an object has while it’s in motion 7. speed – how fast an object’s position changes with time 8. velocity – the speed and direction of a moving object 9. acceleration – change in velocity with respect to time 10. balanced forces – forces that cancel each other out when acting together on a single object 11. unbalanced forces – forces that do not cancel each other out when acting together on a single object 12. action – the force one object applies to a second 13. reaction – the force with which an object responses to an action, as in Newton’s third law of motion 14. gravity – the force of attraction between any two objects due to their mass 15. weight – the force of gravity between Earth and an object 16. work – the use of force to move an object a certain distance 17. simple machine – a machine with few moving parts, making it easier to do work 18. lever – a simple machine made of a rigid bar and a fixed pivot point, called the fulcrum (pliers) 19. screw – is an inclined plane wrapped in a spiral around a cylinder or cone. Used to hold things like wood and metal together. (bottom of a light bulb, jar lid, screw) 20. inclined plane - is a flat, slanted surface that makes it easier to move heavy objects to higher levels. (loading ramps, slide) 21. wedge – is an inclined plane that is used as a tool for cutting or separating things. Two inclined planes back to back. (needles, ax head, knife blades, log splitters) 22. wheel and axle – when a large diameter wheel rotates in a circle around a smaller diameter axle. (doorknobs, screwdriver, bicycle wheel) 23. pulley – is a wheel with a groove in the rim (flag pole) 24. fulcrum – a pivot point of a lever 25. resistance arm – the part of a lever the applies force to the load the machine acts against. 26. effort arm – the part of a lever that applies force to the resistant arm