1. Physics Day 8 AIM: How do we describe motion? LO:Choose coordinate systems for motion problems LO:Differentiate between scalar and vector quantities LO:Define a displacement vector and determine time AGENDA Do Now 1D Motion Worksheet Homework Do Now:

2. Speed Velocity, Acceleration FLHS Physics Ms. Li

3. Kinematics The study of motion in a straight line. One-dimensional motion Motion without rotation

4. How Far - Distance In the metric system we measure distance in Meters (m) and Kilometers (km) 1 kilometer = 1000 meters. Distance traveled is the route traveled Displacement is the short cut between start and end.

5. Speed How “fast” something is moving. Usually calculated as average speed Speed is a Scalar (no direction) Average speed = distance traveled time elapsed Unit is m/s

6. Frame of Reference Motion is measured relative to a frame of reference A frame of reference is assumed to be fixed in place. When motion is stated the frame of reference is indicated  Ex: What is the speed of the boat relative to the ground.

7. Velocity Vector quantity Includes speed and direction Formula:  Average velocity = displacement time elapsed Units are m/s

8. Velocity v = d f – d i =  d t f – t i  t  means change in Unit = m/s

9. Acceleration Defined as a change in velocity Can be calculated as average acceleration. Formula: average accel. = change in velocity time elapsed Unit = m/s 2

10. Acceleration The relationship between acceleration, speed, and time can be written as: Using symbols, the same relationship can be written as:

11. Acceleration 2 Where a = acceleration Δv= change in speed Δt = time interval or change in time, for the time that the change in speed to happen.

12. Example: My new corvette can go from 0 meters/second to 27 meters/second (60 miles per hour) in 4.6 seconds Find the acceleration. http://www.chevrolet.com/corvette/ http://www.chevrolet.com/corvette/

13. Units Mathematically, meters per second per second is equal to meters per second squared. Therefore, when you use "m" and "s" as abbreviations for meters and seconds, you can shorten the unit of acceleration to m/s 2. The following ways of stating the unit of acceleration are the same: (m/s)/s m/s 2