2. Vector vs. Scalar Quantities A vector quantity is a quantity that has both magnitude and direction. Velocity, acceleration, and force are examples of vector quantities. A scalar quantity is a quantity that has magnitude, but no direction. Time, mass, volume, and speed are examples of scalar quantities.

3. What is Velocity? Velocity is a vector quantity that refers to "the rate at which an object changes its position.” Velocity is speed in a given direction. Example: Marsha is driving 35 mph in the west direction. Velocity=change in distance/change in time You must include direction when talking about velocity!

4. What is Acceleration? Acceleration is the rate of change in velocity over time. Acceleration is measured in meters per second per second (m/s/s) Acceleration= Final velocity-Starting velocity/time

5. Acceleration continued… The acceleration formula can be rearranged to solve for other variables such as final speed (v2) and time (t). vf = vi + (a × t) t=vf-vi/a

6. Acceleration practice problems A skater increases her velocity from 2.0 m/sec to 10.0 m/sec in 3.0 seconds. What is the skater’s acceleration? Beginning speed = 2.0 m/sec Final speed = 10.0 m/sec Change in time = 3 seconds Acceleration=10.0m/s-2.0m/s divided by 3sec= 8.0m/s divided by 3 sec=2.7m/s/s

7. Acceleration practice problems A car accelerates at a rate of 3.0 m/sec2. If its original speed is 8.0 m/sec, how many seconds will it take the car to reach a final speed of 25.0 m/sec? Beginning speed = 8.0 m/sec Final speed = 25.0 m/sec Acceleration = 3.0 m/sec2 What are we solving for? What is our formula?

8. We are solving for time! Time=final velocity-initial velocity divided by acceleration. 25.0m/s-8.0m/s divided by 3.0m/s/s Time=17.0m/s divided by 3.0m/s/s Time=5.7seconds