Important Formulas - Problems on Trains1. xkm/hr =x518m/s
2. ym/s =y185km/hr
3. Speed = distance/times = d/t
4. velocity = displacement/timev = d/t
5. Time taken by a train x meters long to pass a pole or
standing man or a post= Time taken by the train to travel x
meters.
6. Time taken by a train x meters long to pass an object of
length y meters= Time taken by the train to travel (x + y)
metres.
7. Suppose two trains or two objects are moving in the same
direction at v1 m/s and v2 m/s where v1 > v2,then their relative
speed = (v1 v2) m/s
8. Suppose two trains or two objects are moving in opposite
directions at v1 m/s and v2 m/s ,then their relative speed = (v1+
v2) m/s
9. Assume two trains of length x metres and y metres are moving
in opposite directions at v1 m/s and v2 m/s, ThenThe time taken by
the trains to cross each other = (x+y) / (v1+v2) seconds
10. Assume two trains of length x metres and y metres are moving
in the same direction at at v1 m/s and v2 m/s where v1 > v2,
ThenThe time taken by the faster train to cross the slower train =
(x+y) / (v1-v2) seconds
11. Assume that two trains (objects) start from two points P and
Q towards each other at the same time and after crossing they take
p and q seconds to reach Q and P respectively. Then,
A's speed: B's speed =q:p
