Answer:
0.39
Explanation:
In order not to slide, you must have exactly the same acceleration of the train:
[tex]a=0.39 g[/tex]
where
g = 9.81 m/s^2
There is only one force acting on you: the static frictional force that "pulls" you forward, and it is given by
[tex]F_s = \mu_s mg[/tex]
According to Newton's second law, the net force acting on you (so, the frictional force) must be equal to your mass times the acceleration, so we have
[tex]F= ma = \mu_s mg[/tex]
from which we find
[tex]\mu_s = \frac{a}{g}=\frac{0.39 g}{g}=0.39[/tex]
so, the minimum coefficient of static friction must be 0.39.
