Question

The driver of a train A moving with a uniform speed of 30 ms⁻¹ sees another train B moving with uniform speed 10 ms⁻¹ on the same track in the same direction. He immediately applies brakes and achieves a uniform retardation of 2ms⁻¹ and and finally stops. To avoid collision, the minimum distance between the trains must be

(a) 140 m

(b) 75 m

(c) 80 m

(d) 120 m

Answer 1

Answer is : (b) 75 m

The distance of A is given by

Putting the value of t in Eq. (i), we get

∴ s_min = 20 x 15 - 225 = 75 m