# Friction

## 14 terms

### Newton's Third Law

for every action, there is an equal and opposite reaction

### Momentum

a quantity defined as the product of the mass and velocity of an object

### Law Of Conservation Of Momentum

in the absence of an external force, the momentum of a system remains unchanged

### Impulse

the product of force x time that causes a change in momentum

### Collision

When two or more objects hit each other

### Elastic Collision

a collision between ideally elastic bodies in which the final and initial kinetic energies are the same

### Inelastic Collision

a type of collision where the total kinetic friction after the collision is less than it was before the collision

### Friction

the force that opposes the motion of one surface as it moves across another surface

### Sliding Friction

a force that opposes the direction of motion of an object as it slides over a surface

### Static Friction

frictional force that prevents two surfaces from sliding past each other

### Lubricants

substances that reduce friction

### Ball Bearing

bearings containing small metal balls

### Magnetic Levitation

a method used to reduce friction using air layers

### Rolling Friction

friction that occurs when an object rolls over a surface