# Newton's laws, force, friction

## 20 terms

A push or pull

### motion

to change position

### average speed

The distance traveled over a certain period of time

### acceleration

a change in speed or direction

### velocity

the speed of an object in a particular direction

### gravity

a force of attraction between two objects depending on the mass of those objects.

### friction

a force that resists motion by way of contact between two things

### sliding friction

a force that resists motion as two things slide across each other

### rolling friction

resistance of motion caused by a round object rolling across another object

### fluid friction

a force that resists motion of an object due to a liquid or gas

### Newton

Unit used to measure a force (N).

### Newton's Second Law

An object will accelerate, depending on the object's mass, and the forces exserted on the object.

### Newton's Third Law

For every action force, there is an equal but opposite reaction force

### Newton's First Law

In object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an unbalanced force.

### unbalanced force

When two forces acting on each other cause an object to move.

### balanced force

When forces acting on each other equally and in opposite directions which cause no movement of an object

### momentum

A measure of the motion of an object due to its mass and velocity.

### inertia

The tendancy of an object to resist movement or a change in movement.

### static friction

Two objects not in motion due to their contact

### reference point

A fixed point that you may use to determine if something is moving.