posted by help on .
A train moving at a constant speed of 68.0 km/h moves east for 33.0 min, then in a direction 40.0° east of due north for 30.0 min, and then west for 59.0 min. What is the average velocity of the train during this run?
The key is finding the final position.
1) It goes 68*33/60 km east
2) it goes 68*30/60 40 deg E of N. Converting that to E and N displacements..
it goes 60(30/60)sin40 East
it goes 60(30/60)cos40 North
3) it goes E for 68(-59/60) Notice the negative sign which changes West to East.
Now add up the East components.
That gives you the net East.
Now add up the N components.
Now use Pythogerean theorum
Magnitude avg velocity=displacement/timetotal.