Speed, Velocity, and Acceleration

Motion What is Motion? Motion is a change in position. Example:

Speed What is Speed? Speed is a Rate of Motion. (Change over time) Types of SpeedTypes of Speed: 1) Instantaneous Speed 2) Constant Speed 3) Average Speed

Instantaneous Speed This is the rate of motion at any given point of time. Example: The speedometer of cars.

Constant Speed A speed that does not vary. Example: Cruise control in cars. Set cruise at 55 mph on long trips and your car will stay at 55 mph.

Average Speed An Average of all of the instantaneous speeds gathered over a period of time. In other words: –It is the Total distance traveled divided by the total time it took to travel.

Speed Formula Example: What is the speed if a car travels 200 miles in 4 hours? Answer = 50 mph V= t d

Velocity What is Velocity? Velocity is the rate of motion in a specific direction. (e.i. Speed and Direction) If either speed or direction change, then VELOCITY changes.

Change in Velocity A car is traveling west on route 22 at 45 mph. When it approaches the light at sheets, it slows to 5 mph. Did Velocity change? YES: The Speed changed but direction stayed the same.

Change in Velocity A ball is thrown against a wall at 25 mph and bounces back to the person at the 25 mph. Did Velocity change? YES: The Direction changed but speed stayed the same.

Acceleration What is Acceleration? Acceleration is the rate of change of Velocity. a t = V f - V i t = VV

Standard SI Units Velocity & Speed: Meters per Second m s Acceleration: meters per Second Squared m s2s2