Plz solve this question
Solution
time taken by the train to reach the railway crossing will be
t =distance it has to travel / speed of the train
so,
t = 1km / 90km/hr = 0.011 hours
or
t = 39.6 secs.
now, the car should reach the crossing in exactly this amount of time.
we know that
s = ut + (1/2)at2 = 500m
or the acceleration required will be
a = 2(s - ut) / t2
or
a = 2 (500 - 2x39.6) / 39.62
or
a = 841.6 / 1568.16
so, the car must accelerate by
a = 0.536 m/s2
Final velocity
v2 = u2 + 2as