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Hey guys I need a help with the set up for a physics question?
An automobile and train move together along parallel paths at 22.7 m/s. The automobile then undergoes a uniform acceleration of −4 m/s2 because of a red light and comes to rest. It remains at rest for 60 s, then accelerates back to a speed of 22.7 m/s at a rate of 3.75 m/s2.
How far behind the train is the automobile when it reaches the speed of 22.7 m/s, assuming that the train speed has remained at 22.7 m/s? Answer in units of m.
Any help is appreciated and thank you!
1 Answer
- oubaasLv 72 years ago
An automobile and train move together along parallel paths at 22.7 m/s. The automobile then undergoes a uniform acceleration of −4 m/s^2 because of a red light and comes to rest.
It remains at rest for 60 s, then accelerates back to a speed of 22.7 m/s at a rate of 3.75 m/s^2
How far behind the train (d) is the automobile when it reaches the speed of 22.7 m/s, assuming that the train speed has remained at 22.7 m/s?
car braking time tb = (0-22.7)/-4 = 5.675 sec
car accelerating time ta = 22.7/3.75 = 6.053 sec
distance d = 22.7*((5.675+6.053)/2+60) = 1,628 m
in just three lines
