Presentation Transcript
Objectives :Objectives Describe the relationship between velocity and acceleration
Define acceleration and deceleration
Calculate acceleration
Scientists have a special way to measure a change in velocity: :Scientists have a special way to measure a change in velocity: Acceleration Acceleration is a change in velocity over time.
Slide 3:If you’re speeding up, you have positive acceleration.
If you’re slowing down, you have negative acceleration. The Way Acceleration Works:
final velocity – initial velocity time :final velocity – initial velocity time Acceleration Formula
A = Vf – Vi T :A = Vf – Vi T Acceleration equation
A = V T :A = V T is pronounced delta
Acceleration units :Acceleration units km/hr/s kilometers per hour per second km/hr/hr or km/hr2 kilometers per hour per hour m/s/s or m/s2 meters per second per second
Example problem :Example problem A roller coaster’s speed at the top of a hill is 10 m/s. Two seconds later, it reaches the bottom of the hill with a speed of 26 m/s. What is the acceleration of the roller coaster? Vi T Vf
A = V T :A = V T Final velocity = 26 m/s
Initial velocity = 10 m/s
Time = 2 s A = 26 m/s – 10 m/s
2s = 16 m/s
2s = 8 m/s/s 8 m/s2
Example Problem :Example Problem At the end of a race, a bicycle is decelerated from a velocity of 12 m/s to a rest position in 30 seconds. What is the deceleration of this bicycle? Vi T Vf = 0 m/s
A = V T :A = V T Final velocity = 0 m/s
Initial velocity = 12 m/s
Time = 30 s A = 0 m/s – 12 m/s
30s = -12 m/s
30s = -0.4 m/s/s = -0.4 m/s2