Question: Reference Frame Physics!!!?
Two students, Jim and Sarah, are walking to different classrooms from the same cafeteria. How does Jim's velocity in Sarah's Reference Frame relate to Sarah's velocity in Jim's reference frame?
a. No relationship
b. They are identical
c. They are equal but opposite
d. There is not enough information
For some reason I am just not getting this answer! :( Could someone please explain it to me?
I think the answer to this question is c - they are equal but opposite.
First remember that velocity is a vector quantity - it has both a magnitude and a direction
Jim and Sarah both leave from the same point, but in 2 different directions. They are therefore moving apart from each other. The rate at which they move apart is the magnitude of this vector, which will be the same in both frames of reference (i.e. the speed is equal - hence the 'equal' bit of the answer). The direction is opposite for each frame of reference however.
Imagine you are Jim. You leave the caferia at 2m/s to a classroom to the west. Sarah leaves at 2m/s to a classroom to the east. From your point of view, Sarah would be moving away from you at 4m/s to the east. Now put yourself in Sarah's shoes. This time Jim would be moving away from you at 4m/s to the west.
When thinking of frames of reference, try to imagine what you would see when you are in that particular frame of reference.