Question

Each 50 metre long are travelling in opposite directions with respective velocities 10 metre per second and 50 metre per second the time of crossing is

Answer 1

Let the two bodies be A and B

Velocity of A = 10m/s

Velocity of B = 50m/s

since they are moving towards each other; velocity of A w.r.t B = 10+50                    

                                                                                                         = 60m/s

So when A is travelling with 60m/s B is assumed to be at rest.

thus the total distance to be travelled by A to cross B = 50+50

                                                                                          = 100m

time taken = 100/ 60

                 = 1.67 s