15 terms

# 6th grade science vocabulary words

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Force
- a push or pull
Net force
- the combination of forces acting on an object
* opposite forces or direction- subtract
Balanced force
- opposite forces acting on an object that cancel each other out
* Net force is always 0
*object does not move
*does not change velocity
Unbalanced force
- unequal forces that act on an object
* net force is never 0
* changes velocity of object
Motion
- any change in position of an object
Speed
- the distance an object travels in a unit of time
* formula: distance /time = speed
Velocity
- speed in a particular direction
Acceleration
- any change in velocity
* speed up
* slow down
* change direction
* start
* stop
Friction
- the force that resists the motion of two touching objects
* resists motion
Newton's 1st law of motion
- An object at rest will remain at rest and an object in motion will continue moving in a straight line at a constant speed until an outside force acts against it.
Momentum
- a measure of how hard it is to stop an object's motion
* depends on mass and velocity
* more mass= more momentum
* more velocity = more momentum
Newton's 2nd law of motion
- An object's acceleration depends on the size and direction of the force acting on it and the mass of the object.
What affects acceleration?
1. size of the force
2. direction of the force
3. mass of the object
Newton's 3rd law of motion
- For every action there is an equal and opposite reaction
* forces always act in pairs
* equal and opposite pairs
Inertia
- the tendency of an object to resist a change in its motion
Law of conservation of momentum
- momentum can not be transferred to another object
(unless an outside force acts on it, friction or gravity)