Question

a train passes telegraph post in 40 seconds moving at rate of 36 km/h. Then , the length of train is
a-400m
b-500m
c-450m
d-395m

Answer 1

GIVEN,

speed of train = 36 kmph, and it passes a pole in 40 seconds.

TO FIND,

The length of the train.

SOLUTION,

the train is moving at 36kmph

converting this to m/s= 36*$\frac{5}{18}$

                                    = 10 m/s

if the train is passing a pole in 40 seconds that is a static object, therefore the time required to cross the pole is also the distance traveled by the train of its own.

Distance traveled by train= length of train= speed* time

                                                                     = 10 m/s * 40seconds

                                                                     = 400m

HENCE THE LENGTH OF THE TRAIN WHICH IS ALSO THE DISTANCE TRAVELED BY TRAIN IN 40 SECONDS IS 400M.