On a two-lane road, car A is travelling with a speed of 36 km h-1. Two cars B and C approach car A in opposite directions with a speed of 54 km h-1 each. At a certain instant, when the distance AB is equal to AC, both being 1 km, B decides to overtake A before C does. What minimum acceleration of car B is required to avoid an accident ?
Say observer is A. Velocities now would be relative.
1=(54-36)t+(1/2)at2.........(1)
1=(54+36)t.....
t=1/90, a can be obtained from equation (1) in Km/hr2.