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Unit 4 Vocabulary
Term | Definition |
---|---|
distance | length between two places |
position | object’s location compared to other things |
motion | change in an object’s position compared to a fixed object |
speed | how fast an object’s position changes with time at any given moment (speed= distance ÷ time) |
velocity | description of a moving object’s speed and direction |
acceleration | measure of the change in velocity during a period of time (acceleration = change in speed ÷ time) |
force | any push or pull on an object |
contact | force- force applied when two objects touch |
noncontact force | a force that one object can apply without touching |
net force | combination of all the forces acting on an object |
balanced force | forces acting on an object that combine to form a net force of zero |
unbalanced force | forces acting on an object that combine to form a net force that is not zero |
gravity | attractive force that exists between all objects that have mass |
friction | force that opposes the motion of an object |
air resistance | fluid friction between the surface of an object and the air |
elastic force | force exerted by a material when it is stretched or compressed |
tension force | pulling force applied when an object is stretched |
Newton’s 1st law of motion | an object at rest tends to stay at rest and an object in constant motion tends to stay in motion unless acted upon by an unbalanced force. |
Newton’s 2nd law of motion | acceleration depends on the object’s mass and the amount of net force applied to it |
Newton’s 3rd law of motion | when one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object (action, reaction forces) |
Action force | push of the first object on the second |
Reaction force | push of the second object back on the first |