# Physical Science Chapter 9 Motion and Energy

## 24 terms

### motion

The state in which one object's distance from another is changing.

### reference point

A place or object used for comparison to describe the position or motion of a person or object.

### distance

The length of a path between two points.

### displacement

The length and direction of a straight line between starting and ending points.

### vector

A measurable quantity that has both magnitude and direction.

### speed

The distance an object travels in a certain period of time without regard to direction.

### instantaneous speed

The speed of an object at any given instant.

### velocity

Speed in a given direction.

### slope

The steepness of a line on a graph equal to its vertical change divided by its horizontal change.

### acceleration

The rate at which velocity changes with time.

### work

A word that describes what is done on an object when a force is exerted on an object that causes it to move.

### energy

The ability to do work or cause change.

### kinetic energy

The energy that an object has due to its motion.

### potential energy

Stored energy that results from the position or shape of an object.

### gravitational potential energy

The potential energy related to an object's height.

### elastic potential energy

The energy of stretched or compressed objects.

### mechanical energy

An object's combined kinetic energy an potential energy.

### law of conservation of energy

The rule that energy cannot be created nor destroyed.

### average speed

The overall rate of speed at which an object moves; calculated by dividing the total distance an object travels by the total time.

Distance/Time

### Acceleration =

Final velocity - Initial velocity/Time

### Kinetic Energy =

1/2(Mass)(Speed)(Speed)

Weight X Height

### Mechanical energy =

Potential energy + Kinetic energy