A train moving at 20 m s⁻¹ comes to rest when brakes are applied 500 m before a station. If the same brakes are applied only 250 m before the station, the train crosses the station with speed √x m s⁻¹. Find x.
Physics · Circular Motion
JEE Mains JEE Advanced

Question

A train moving at 20 m s⁻¹ comes to rest when brakes are applied 500 m before a station. If the same brakes are applied only 250 m before the station, the train crosses the station with speed √x m s⁻¹. Find x.

Physics · Circular Motion

G1 Physics · Accepted Answer

For the first case: v² = u² + 2as 0 = 20² + 2a(500) a = −0.4 m s⁻² For braking distance 250 m: v² = 20² + 2(−0.4)(250) = 400 − 200 = 200 So: v = √200 m s⁻¹ Hence x = 200.