Question
A car motor is slowing down from 4200 to 1100 rpm over 4 sec. The negative acceleration is approximately 81(I don't have the problem in front of me). How many revolutions does the motor make over those 4 sec. I can't figure this out because the revolutions are getting slower and slower and therefore each revolution takes more and more time.
Answers
drwls
The units of your "81" number are apparently radians/s^2. That should have been included.
You can use the fact that the average rpm during deceleration is 5300/2 = 2650 rev/min = 277.5 rad/s. Since 4 s = 1/15 minute, the number of engine revolutions made would be
2650/15 = 176.7
You can use the fact that the average rpm during deceleration is 5300/2 = 2650 rev/min = 277.5 rad/s. Since 4 s = 1/15 minute, the number of engine revolutions made would be
2650/15 = 176.7