AP Physics 1 1.1-1.2

Distance

The measure of length between objects or points without regard for direction.

Displacement

The change in position of an object.

Vector

A quantity that has direction as well as magnitude.

Example: Displacement, Velocity and Acceleration

Scalar

Quantities that have no direction associated with them.

Example: Distance and Speed

Resultant Vector

The single vector that represents the sum of two or more individual vectors.

Speed

The magnitude of the change of its position per unit of time.

Aka a positive number with units.

Velocity

The magnitude of how fast an object is moving and the direction in which it’s moving.

Acceleration

How rapidly the velocity of an object is changing.

Distance Formula

Distance= Speed x Time

Displacement Formula

Δx= x₂-x₁

Displacement= Final - Initial

Speed Formula

Speed= Distance Traveled/Time Elapsed

s= d/t

Velocity Formula

v= Δx / Δt

Velocity= Displacement / Time Elapsed

*Average speed is not necessarily equal to the magnitude of the average velocity

Acceleration Formula

a= Δv / Δt

Acceleration= Change in Velocity / Time Elapsed

Positive/Negative Acceleration

Positive= right

Negative= left

The acceleration vector (orange) points to the left because the car slows down as it moves to the right.

Positive/Negative Displacement

Positive Displacement= Right

Example: Δx= 30.0m - 10.0m = 20.0m

Negative Displacement= Left

Example: Δx= 10,0m - 30.0m= -20.0m

Positive/Negative Velocity

The average velocity is positive for an object moving to the right along the x axis and negative when the object moves to the left.

*The direction of the average velocity is always the same as the direction of the displacement.