# Problems on Trains formulas:

1.

To convert from km/hrto m/sec:Multiply by5/18m/s.2.

To convert from m/sec to Km/hr:Multiply by18/5km/hr.3. Formulas for finding Speed, Time and Distance

4. Time taken by a train of length L meters to pass a pole or standing man or a signal post is equal to the time taken by the train to cover L meters.

5. Time taken by a train of length l meters to pass a stationery object of length b meters is the time taken by the train to cover

(l + b) meters.6. Suppose two trains or two objects bodies are moving in the same direction at u m/s and v m/s, where u > v, then their relative speed is =

(u – v) m/s.7. Suppose two trains or two objects bodies are moving in opposite directions at u m/s and v m/s, then their relative speed is =

(u + v) m/s.8. If two trains of length a metres and b metres are moving in opposite directions at u m/s and v m/s, then:

The time taken by the trains to cross each other =

(a + b)/(u + v) sec.9. If two trains of length a metres and b metres are moving in the same direction at u m/s and v m/s, then:

The time taken by the faster train to cross the slower train =

(a + b)/(u – v) sec.10. If two trains (or bodies) start at the same time from points A and B towards each other and after crossing they take a and b sec in reaching B and A respectively, then:

(A’s speed) : (B’s speed) = (b : a)