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S8P3.a, b, c
S8P3.a
Question | Answer |
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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 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 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. |
interia | 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 of 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 plane | 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. |