Question

47.
Two trains A&B, each of length 100 m, are running on parallel tracks . If one were to completely
overtake the other, travelling in the same direction, it would take 20s. It would take 10's for one to
completely cross the other, if the trains are travelling in the opposite direction. Calculate the
velocities of trains A & B.​

Answer 1

Answer:

HERE IS YOUR SOLUTION;

◆ Let u & v be the velocity of the two trains named A & B.

While overtaking the relative velocity of train A with respect to B = u - v.

While crossing, the relative velocity of train A with respect to B = u + v.

◆Total distance to be travelled by Train A while crossing = 100 + 100 = 200.

So,

20 = 200 ÷ u-v

=> u - v = 10....1)

Also,

10 = 200 ÷ u + v

=> u + v = 20.......2)

◆◆ On solving the equation 1 & 2, we get;◆◆

u = 15 M/S of the train A / First Train.

v= 5 M/S of the train B / Second Train.

HOPE IT HELPS

Explanation:

Answer 2

sorry i made a mistake so hd to write all over again.Bring one train to rest as i did and add that velocity to the other train. This is very useful in relative velocity. Then assume a point on the moving train and measure the total distance it covers by the time the train completely overtakes the other train.Practice little u will understand how to use it. Use the point method only for these type of train qstions. hope u understud!!