Answer:
Explanation:
Velocity of train 130 km /hr
distance of crossing s = 500 m = .5 km
Time taken by train to reach crossing = .5 / 130 = .003846 hr = 13.85 s
Time taken by gangster to reach the crossing = t
initial velocity u = 100km/h = 27.77 m /s
distance of crossing s = 750 m
acceleration a = 4 m /s
s = ut + .5 a t²
750 = 27.77 t + .5 x 4 x t²
2 t² + 27.77 t - 750 = 0
t = - 27.77 ± √(27.77² + 4 x 2 x 750) / 2 x 2
= - 27.77 ±√ ( 771.17 + 6000) / 4
= - 27.77 ±82.28 / 4
= 13.62 s
So this time is less than time taken by train so it will be able to cross the crossing before train arrives .