# Shared Flashcard Set

## Details

Unit 8-Forces/Motion and Work/Machines
vocab cards
14
Science
02/26/2013

Term
 1. air resistance
Definition
 A force that opposes the motion of objects that are falling through the air. (air friction)
Term
 vacuum
Definition
 A space where there is no matter.  Outer space is an example of this.
Term
 inertia
Definition
 the tendency of an object to stay at rest or in motion (objects just want to keep on doing whatever it is doing)
Term
 Newton's 1st Law of Motion
Definition
 an object at rest will remain at rest, an object in motion will remain in motion UNLESS acted on by an UNBALANCED force.
Term
 Newton's 2nd Law of Motion
Definition
 The acceleration of an object depends on the mass of the object and the amount of force applied. F = m x a
Term
 formula for force
Definition
 F= ma (Force= mass x acceleration)
Term
 Newton's 3rd Law of Motion
Definition
 For every action there is an equal and opposite reaction. Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Forces always work in pairs. Example-a rocket shipping blasting off.  The gases push down and the rocket pushes up.
Term
 force pairs
Definition
 All forces act in pairs. When a force is exerted, there is always a reaction force. Example-Hitting a baseball bat, the bat exerts a force on the ball and sends the ball flying.
Term
 momentum
Definition
 A property of all moving objects. Momentum is determined by two factors:  mass and velocity Momentum = mass x velocity
Term
 Law of Conservation of Momentum
Definition
 Momentum can be transferred but cannot be lost within a system. When one moving object collides with another moving object, the motion of both objects changes.
Term
 work
Definition
 The transfer of energy to an object using a force that causes the object to move in the direction of the force.
Term
 Formula for Work
Definition
 W= F x d
Term
 joule (J)
Definition
 The unit/label for work
Term
 machine
Definition
 A device that helps do work by either overcoming a force or changing the direction of the applied force.
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