A train overtakes 2 people who are walking in the same direction as the train is going, at the speed of 2 km/h and 4km/h and the train passes them in 9 & 10 seconds respectively. Find the length and speed of the train.

Question

anonymous · Answer

Let l be length, s be speed

then
(s   -   5/9)9=l
(s  -  10/9)10=l

anonymous · Answer

I did not understand that

anonymous · Answer

the length of the train, in this case the distance traveled , is the time in overtaking multiplied by the relative velocity

anonymous · Answer

Okay

anonymous · Answer

him1618 - How do you calculate relative velocity?

anonymous · Answer

V(A wrt B) = V(A) - V(B)
This is a vector equation which can be read as:
Velocity vector of A with respect to B equals Velocity vector of A - Velocity vector of B

anonymous · Answer

Ok - thanks!