KinematicsAcceleration

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Motion with Constant Acceleration

Instantaneous Acceleration

Acceleration

KinematicsAcceleration

2

Acceleration measures the change in the motion of an objectThis change can happen in magnitude or direction.

As the bee moves to a new flower, he speeds up at takeoff and slows down as he lands.

Both speeding up and slowing down are acceleration.

As he leaves the scene, his speed is constant, but his direction changes.

This change in direction is also an acceleration!

Acceleration a

KinematicsAcceleration

3

The direction and quantity of “the change of motion” of a particle is given by its acceleration.

The average acceleration of a particle (whether or not the change in motion is uniform) is given be a simple equation …

In words, we would say this equation tells us that “the average acceleration of a particle is the change in its velocity over the entire interval during which it moved”.

The slope of this line is the x-component of the

average acceleration.

Average Acceleration

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KinematicsAcceleration

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Acceleration is constant if it does not change.

This means that the quantity (known as the magnitude) and the direction stay the same.

If the velocity vs. time graph of a particle’s motion is a straight line,

then the average acceleration is the slope of this line and this component of the change in motion is uniform.

Motion with Constant Acceleration (Uniform Change in Motion)

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KinematicsAcceleration

5

A way to model the change in motion of a particle is to graph acceleration vs. time.

Acceleration is the derivative (slope) of the velocity over time.

Acceleration vs. Time Graph

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0s 5s 8s4s 7s2s 3s 6s1s 0s 5s 8s4s 7s2s 3s 6s1s

ta vs.

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