1. 2-Dimensional Motion Part III
Relative Motion:
3.4

2. Frame of Reference
The frame of reference is the coordinate system from which you are measuring motion.
The direction and magnitude of motion depend on where the “viewer” is located.
Think of the movie Vantage Point
People located in different places in Tenneman Square saw different things.
The shooter may have been on the left of one person, but the right of another
Someone above saw the bullet whiz by with negative position, but someone below “saw” the bullet move from above.
The shooter saw the bullet travel away from him, and the president “saw” (or would have seen) it coming at him.

3. Relative Velocity Imagine being in a car and passing another car:
Vse = -80km/h north (velocity of slower car relative to earth)
Vfe = +90 km/h north (velocity of faster car relative to earth)
We want to know Vfs (fast car relative to slow car)
Now we draw the vectors

4. A boat heading north crosses a wider river with a velocity of 10
A boat heading north crosses a wider river with a velocity of km/h relative to the water. The river has a uniform velocity of 5.00 km/h due east. Determine the boat’s velocity with respect to an observer on the shore.

5. A Passenger at the rear of a train traveling at 15 m/s relative to earth throws a baseball with a speed of 15 m/s in the direction opposite the motion of the train. What is the velocity of the baseball relative to Earth as it leaves the throwers hand? Show your work!

6. A pet-store supply truck moves at 25. 0 m/s north along the highway
A pet-store supply truck moves at 25.0 m/s north along the highway. Inside, a dog moves at 1.75 m/s at an angle of 35.0° east of north. What is the velocity of the dog relative to the road?