Problems on Train - Part 1

 

PROBLEMS ON TRAIN

Before, entering into the topic one must know the common relation which is

S=D/T

S- speed of the train in (km/hr) or (m/s)

D- distance of the train or object in (km) or (m)

T- time it takes in (hr) or (sec)

CONVERSION:

Km/hr to m/s multiply by 5/18

m/s to km/hr multiply by 18/5

what is this 5/18???

It is 1 km equals to 1000m & 1 hr equals to 3600secs

So 1km/1hr = 1000m/3600secs on further simplifying 5/18 m/s.

NOTE- always convert speed rather than time & distance.

Some factors to be known before solving the problem based on this, the problem classified into several types…

LENGTH OBJECTS- Platforms, bridges, tunnels, trains

NO LENGTH OBJECTS- Tree, man, pole, post, car, bus.

WHEN THE TRAIN CROSSES NO LENGTH OBJECTS
IF, STANDING	DIRECTION	SPEED	DISTANCE
	-	Train speed S	Train distance D
IF, MOVING	DIRECTION	SPEED	DISTANCE
	SAME	S1-S2 S1-speed of train S2-speed of man/car etc	Train distance D
	OPPOSITE	S1+S2 S1-speed of train S2-speed of car/man etc	Train distance D

 

 

WHEN THE TRAIN CROSSES LENGTH OBJECTS
IF, STANDING	DIRECTION	SPEED	DISTANCE
	-	Train speed S	D1+D2 D1- distance of train D2- Distance of length objects
IF, MOVING	DIRECTION	SPEED	DISTANCE
s	SAME	S1-S2 S1-speed of train P S2-speed of train Q	D1+D2 D1-distance of train P D2-distance of train Q
	OPPOSITE	S1+S2 S1-speed of train P S2-speed of train Q	D1+D2 D1-distance of train P D2-distance of train Q