# Ch15.1-15.3

## 11 terms

### position

Location of an object.

### motion

A change of position of an object.

### speed

The measure of an object's change in position during a unit of time. Speed=distance/time E.g.If you travel 225 km in 3 hours you can find your speed 225km/3hr=75km/hr. Speed tells you only how quickly or slowly an object moves. It doesn't tell you the direction of motion.

### velocity

The measure of the speed and direction of motion of an object.

### acceleration

Any change in the speed or direction of an object's motion.

### force

A pull or a push of any kind.

### inertia

The property of matter that keeps an object at rest or keeps it moving in a straight line.

### Gravity

The force of attraction between Earth and other objects.

### gravitation

A force that acts between any two objects and pulls them together.

### weight

A measure of the gravitational force acting on a object.

### friction

The force that resists motion between objects that are in contact.