Question

Two trains p and q are moving along parallel tracks with same uniform speed of 20m/s. The driver of train p decides to overtake train q and accelerates train p by 1m/s^2. After 50 seconds,train p crosses train q.Length of each train is 100 metres.Distance between two trains initially is​

Answer 1

Answer:

The initial distance between the two trains is 1050 m.

Explanation:

Given data:

Two trains p and q are moving at a uniform speed of 20 m/s along the same direction on parallel tracks.

After 50 s, acceleration of train p = 1 m/s²

Length of each train, Lp = Lq = 100 m

To find: initial distance between the two trains

Let us consider the initial distance between the two trains be “x”

After 50 sec, acceleration of train q is zero because it is moving with a uniform speed.

∴ Distance covered by train q in 50 sec, Sq = ut + ½ at²

Or, Sq = 20*50 + ½*0*50² = 1000 m  

And,

∴ Distance covered by train p in 50 sec, Sp = ut + ½ at²

Or, Sp = 20*50 + ½*1*50² = 1000 + 1250 = 2250 m

Now,  

The distance between the two trains, Spq = Sp – Sq = 2250 – 1000 = 1250 m

Since the train p is overtaking train q therefore, the distance Spq must be equal to the sum of lengths of the two trains + the initial distance between the two trains i.e.,

Spq = (Lp+Lq)+x

Or, 1250 = 100 + 100 + x

Or, x = 1250 – 200 = 1050 m  

Answer 2

Explanation:

Here is your answer

distance between the two trains initially = 450m