# Acceleration.

## Presentation on theme: "Acceleration."— Presentation transcript:

Acceleration

How does the rollercoaster’s velocity change over time?
Acceleration A measure of an object’s CHANGE in velocity over a period of time. Velocity is a description of an object’s speed AND direction of travel. How does the rollercoaster’s velocity change over time?

Example If something falls, it will accelerate.
As time goes by, the ball increases its speed continuously.

3 Ways to change Acceleration
Speed up - gets faster as time goes by Slow down – gets slower as time goes by--this is called deceleration. Change direction – remember velocity includes a direction, so if an object turns, we can say it is accelerating too!

Does moving Ferris Wheel demonstrate acceleration? Why or why not?
YES! The Ferris Wheel constantly changes its direction, so it is accelerating

Does this picture demonstrate acceleration? Why or why not?
YES! The baseball’s direction of travel has changed as well as its speed.

Does this picture demonstrate acceleration? Why or why not?
YES! The horses change their speeds dramatically from zero.

Does this picture demonstrate acceleration? Why or why not?
YES! The car slowed down when it hit the pole, thus changing its speed negatively!

How is Acceleration Measured?
Acceleration is a measure of SPEED in a certain TIME…so the units include both speed and time units. For example: Meters/sec every second….or m/s2 (sometimes written m/s/s)

How to Calculate Acceleration
Since acceleration is a change in velocity over time, the formula looks like this: a = Velocity Time If we expand, we get: a = Velocity Final (Vf) – Velocity Initial (Vi) Time