2 Dimensional Motion Part III Relative Motion 3
- Slides: 6
2 -Dimensional Motion Part III Relative Motion: 3. 4
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.
Relative Velocity Imagine being in a car and passing another car: Vse = -80 km/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
A boat heading north crosses a wider river with a velocity of 10. 00 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.
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!
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?
