Unit 2- Force and Motion

Vocabulary- Part I

Frame of Reference

A system of objects that are not moving with respect to

each other

Relative Motion

Movement in relation to a frame of reference

Distance

Length between two points

Displacement

The position with respect to the origin; the length and direction from

the starting point to the ending point.

Speed

Ratio of the distance traveled to the time the object moves

Average Speed

The total distance traveled divided by the total time traveled

Instantaneous Speed

The rate at which an object is moving at a given moment in time.

Velocity

A description of motion involving both speed and direction.

Acceleration

The change in velocity. It can occur when speed changes, when direction changes or when both speed and direction changes.

Free Fall

The movement of an object toward Earth because of gravity.

Constant Acceleration

A steady change in velocity