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course phy 121
2/8 1:13
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? What evidence is there that the acceleration is or is not uniform?aAve=vf-vi /time final-time initial
=20.5-10 / 11-4
=10.5 / 7
=1.5 m/s ^2
vAve= change in distance/ change in time
=115-75 / 11-4
=40 / 7
=5.71 m/s
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Good so far, but you really need to use units throughout your calculations.
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It is not uniform because it takes 7 seconds to travel 40 meters, but in the first half it takes only 4 seconds to travel 75 meters.
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This last answer assumed that the car was at position 0 when t = 0. If that was the case you would be right. However you don't know that. You need an argument that applies only to the given information, with no outside assumptions.
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