Question 350221: A car travels at 60 mph east for 20 min then at 30 mph west for 30 minutes. What is the average speed and average velocity?
Average speed I got, 42 mph. Not sure about average velocity.
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
Your answer for speed is correct. In the first 20 minutes, going 60 miles per hour which is the same thing as 1 mile per minute, the car travels 20 miles. In the next 30 minutes, going 30 miles per hour, which is  mile per minute, the car travels 15 miles. Total distance: 20 plus 15 is 35 miles. Total time 50 minutes which is  hour, so:
 average SPEED.
Notice that speed, being a scalar quantity, doesn't take into consideration the direction of travel.
Velocity, on the other hand, is a vector quantity. It has a magnitude (the scalar speed) and a direction. So if the car went 20 miles east and then turned around and traveled 15 miles west, the car would be 5 miles east of the starting point. 5 miles in of an hour.
and since the ending point was due east of the starting point, the velocity is 6 mph EAST.
John
My calculator said it, I believe it, that settles it
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