Acceleration (Mr. Giles’ car)

Which car will finish first? The Big Race Which car will finish first?

Acceleration Any change in velocity or direction

Accel.= (final velocity – initial velocity)/time Acceleration Acceleration= rate of change in velocity Accel.= (final velocity – initial velocity)/time or a= (vf – vi) / t Units: a=m/s/s

Acceleration (Practice Problem) A roller coaster has a velocity of 10m/sec at the top of a hill. Two seconds later it reaches the bottom of the hill with a velocity of 20m/sec. What is the Acceleration of the roller coaster? Acceleration=(Velocity final – Velocity initial)/time Acc.=(20m/s – 10m/s)/2s Acc.=5m/s/s

If a car is traveling down the road and comes to a stop what is happening to the velocity? Velocity is decreasing If velocity is decreasing it means we have a change in velocity and therefore we can calculate accel. This type of acceleration is also known as Deceleration or negative acceleration.

Negative Acceleration (Deceleration Practice Problem) A roller coaster is moving at 25m/s at the bottom of a hill. Three seconds later it reaches the top of the next hill, moving at 10m/s. What is the deceleration of the roller coaster? Acceleration=(Velocity final – Velocity initial)/time Acc.=(10m/s – 25m/s)/3s Acc.= -5m/s/s

Graphing Acceleration What would the graph look like of these three cars??? Blue Car Red Car Green Car

Graphing Acceleration (Rightward + Changing Velocity) What would the graph of this car look like???