course PHY 121
An automobile traveling a straight line is at point A at clock time t = 4 sec, where it is traveling at 10 m/s, to point B at clock time t = 11 sec, where it is traveling at 20.5 m/s. Point A is 75 meters from the starting point and point B is 115 meters from the starting point.
What are the average velocity and the average acceleration of the automobile during the specified time?
115m – 75m = 40m
11s – 4s = 7s
vAVe=40m / 7s = 5.7m/s
Good.
5.7m/s * 2 =11.4m/s
You can assume that final velocity is double average velocity only when initial velocity on the interval is zero and acceleration is uniform. On this particular interval initial velocity is not zero, and uniformity of acceleration is in question.
11.4m/s / 7s = 1.6 m/s^2
What evidence is there that the acceleration is or is not uniform?
It is not uniform because the acceleration changes.
&#At least part of your solution does not agree with the solution and comments given at the link below. You should view the solution at that link and self-critique as indicated there.
Solution
&#