Question | Answer |
Force | A push or pull exerted on an object in order to change the motion of the object; force has size and direction |
Motion | An object's change in position relative to a reference point |
Reference Point | A stationary object that is used to describe an object's motion |
Speed | The distance traveled divided by the time interval during which the motion occurred |
Velocity | The speed of an object in a particular direction |
Acceleration | The rate at which velocity changes over time; an object accelerates if its speed, direction, or both change |
Friction | A force that oppose motion between two surfaces that are in contact |
Net Force | The combination of all of the forces acting on an object |
Balanced Force | Stated when the net forces acting on an object equal zero |
Unbalanced Force | Stated when the net force acting on an object is not zero |
Inertia | The tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction until an outside force acts on the object |
Gravity | A force attraction between objects that is due to their masses |
Work | The transfer of energy to an object by using a force that causes the object to move in the direction of the force |
Machine | A device that helps do work either by overcoming a force or changing the direction of the applied force |
Inclined Machine | A simple machine that is a straight, slanted surface, which facilitates the raising of loads; a ramp |
Wedge | A simple machine that is made up of two inclined planes and that moves; often used for cutting |
Screw | A simple machine that consists of an inclined plane wrapped around a cylinder |
Lever | A simple machine that consists of a bar that pivots at a fixed point called a fulcrum |
Pulley | A simple machine that consists of a wheel over which a rope, chair, or wire passes |
Wheel and Axle | A simple machine consisting of two circular objects of different sizes; the wheel is the large of the two circular objects |