Acceleration When an object is changing its velocity, we say that the object has acceleration Acceleration is how fast velocity is changing To accelerate, one must: –Speed up –Slow down –AND/OR change direction –Can you give an example of each one of these?

Examples of acceleration Applying the brakes in a car Going around a curve in a car while on cruise control Rolling down a hill Swinging a bucket over your head Hitting a golf ball off a tee

Average Acceleration Formula Average acceleration = change in velocity time required for change a =  v/t = (v f - v i )/t ∆ = change v f = final velocity v i = original (initial) velocity

Remember- acceleration is the rate at which velocity changes, speed is the rate at which distance changes

When acceleration is constant… 1.Velocity increases by the same amount over the same time period 2. And, distance covered per second will always increase

Deceleration is slowing down Zero acceleration is motion at a constant velocity OR not moving at all Can use a v-t graph to show acceleration –+ slope = +acceleration (speed up) –- slope = - acceleration (slow down) –0 slope = no acceleration