1. Frame of reference Physical Definition- a framework that is used for the observation and mathematical description of physical phenomena 2 Simple definitions- 1. how an object experiences or views the motion; 2. object’s point of view

2. How do… ….people account for a frame of reference? Takes into account 2 objects: 1.The observer 1.The object being compared to the observer

3. Consider this still person on the ground as the observer frame of reference, he is observing a plane in the sky He see’s the plane going 100 km/hr Man’s Velocity = 0 km/hr

4. Now… Consider him moving in the opposite direction as the plane at a rate of 25 m/s, while observing the plane still. Relative to the man, what is the plane’s speed? Man’s Velocity = 25 km/hr

5. The speed is… The absolute value of the difference in their two speeds, while considering their directions: Since we are considering opposite directions, we compare them with + and – signs. Since they are opposites, identify one as + and one as -. 25 km/hr – (-100 km/hr) = 125 km/hr The relative speed of the plane with respect to the man is 125 km/hr

6. Now… Consider him moving in the same direction as the plane at a rate of 25 m/s, while observing the plane still. Relative to the man, what is the plane’s speed? Man’s Velocity = 25 km/hr

7. The speed is… The absolute value of the difference in their two speeds, while considering their directions: Since we are considering opposite directions, we compare them with + and – signs. Since they are opposites, identify one as + and one as -. 25 km/hr – (100 km/hr) = - 75 km/hr The relative speed of the plane with respect to the man is 75 km/hr

8. Described with Vectors More importantly, Vector Addition

9. Speed/Velocity Vectors

10. If motion does not fall in a straight line We use create a vector map, and use the Pythagorean Theorem to solve. a 2 + b 2 = c 2

11. Resultant Velocity The resultant velocity is the net velocity of an object with respect to a reference frame.

12. -Relative Motion

13. Example 1 The white speed boat has a velocity of 30km/h,N, and the yellow boat a velocity of 25km/h, N, both with respect to the ground. What is the relative velocity of the white boat with respect to the yellow boat?

14. Example 2- The Bus Ride A passenger is seated on a bus that is traveling with a velocity of 5 m/s, North. If the passenger remains in her seat, what is her velocity: a)with respect to the ground? b)with respect to the bus?

15. Example 2 -continued The passenger decides to approach the driver with a velocity of 1 m/s, N, with respect to the bus, while the bus is moving at 5m/s, N. What is the velocity of the passenger with respect to the ground?

16. Example 3- Airplane and Wind An airplane has a velocity of 40 m/s E. It is facing a headwind of 5m/s West.What is the resultant velocity of the airplane?