trainA is moving at speed of 115 km/hr on a track on the same track 100 m away a trainB is moving at speed 25km/hr what should be the least retardation of trainA so that it doesn't collide? My answer is coming as 63 km/he but it's wrong please help?
V1 = 115km/h = 115,000m/3600s = 31.94 m/s.
V2 = 25km/h = 25,000/3600s = 6.94 m/s.
V2^2 = V1^2 + 2a*d.
d = 100 m., a = ?.
Retardation is negative acceleration. Therefore, "a" will be negative.