A Metra train is at rest at the train station. You are running with a constant speed of #4.0m/s#. When you are 7.50m from the back end of the train, the train begins accelerating away from you at #0.12m/s^2#. Can you catch the train?

If so, when do you catch the train? If not, how close do you get?

1 Answer
Oct 12, 2017



how much time takes the train to attain a speed of 4m/s? from the kinetic equation
#v= a xx t#
you have
#t= v/a= (4 m/s) / (0,12 m/s^2)= 33,3s #
now what distance that do you run in 33 s?
#s= v xx t = 4m/s 33,3s= 133,3 m#
How much is the distance that does the train run in that time?
#s= 1/2 a xx t^2= 1/2 xx 0,12 m/s^2 xx (33,3s)^2= 66,5 m#
since the train travels 66,5 m and you 133,3 m and it is only 7,5 m far, you can catch the train.
But the doors are correctly closed and you can't