# Speed

## 25 terms

### Speed

distance travelled per unit time

### Average Speed

Total distance divided by total time

### Constant Speed

speed that does not change

### Instantaneous Speed

the speed of an object at one instant of time

### Velocity

speed in a given direction

velocity formula

### Acceleration

The rate at which velocity changes

### a = Vf - Vi/t

Acceleration formula

a push or pull

### Contact Force

when one object pushes or pulls another object by touching it

### Non-contact force

Any force on an object by another object that is not touching it.

### Balanced forces

equal forces acting on an object in opposite directions

### Net Forces

the total of all forces acting on an object

### Gravity

(physics) the force of attraction between all masses in the universe

### Weight

a unit used to measure mass

### Newton's First Law

Objects in motion stay in motion unless an outside force acts upon it and objects at rest stay at rest

### Newton's Second Law

Force = Mass * Acceleration

### Newton's 3rd Law

Every action has an equal and opposite reaction

### Inertia

a disposition to remain inactive or inert

### Mass

Amount of matter something takes up

### Friction

effort expended in rubbing one object against another

### Air Resistance

the fluid friction experienced by objects falling through the air

### Terminal Velocity

the constant maximum velocity reached by a body falling through the atmosphere under the attraction of gravity

### Centripetal Force

the inward force on a body moving in a curved path around another body

### Momentum

an impelling force or strength