Question

. Two trains T1, and T2 of the same length are moving
in opposite directions. T1 and T2 crossed an electric
pole in 4 seconds and 6 seconds respectively. If the
speed of T2 is 90 km/hr, find the speed of T1.​

Answer 1

Answer:

135km/hr

Step-by-step explanation:

Convert km/hr into m/s then find the length of train by multiplying with 6s. Now find the speed of T1 by dividing the length by 4s and converging the answer to km/hr

Answer 2

Given:

Two trains T1 & T2 of the same length are moving in opposite directions

T1 and T2 crossed an electric pole in 4 seconds and 6 seconds

Speed of T2 is 90 km/hr

To Find:

Speed of T1

Solution:

The formula for speed is given by,

Speed = $\frac{Distance}{Time}$

To find the length of the T2, we convert the speed of T2 from km/hr to m/sec.

In the given data the speed of the train is given in km\hr. we convert the speed of the train to m/sec by multiplying it by $\frac{5}{18}$ m/sec

1 kilometer = 1000 m & 1 hour = 3600 sec

Now, km\hr can also be written as 1000/3600. On simplifying  1000/3600 further, we get 5/18.

      Distance = Speed × Time

Length of T2 = 90×$\frac{5}{18}$ m/sec × 6 sec

Length of T2  = $\frac{450}{18}$ m/sec × 6 sec

Length of T2  = 25 ×6 m

Length of T2  = 150m

It is given that the length of T1 & T2 are same

 length of T1 = length of T2 = 150 m

To find the Speed of T2

Speed = $\frac{Distance}{Time}$

Distance= 150 m, Time = 4 sec

Speed = $\frac{150 m}{4 sec}$

To convert m/s to km/h, directly multiply the given value of speed by the fraction 18/5

       Speed  =   $\frac{150 }{4 }$ ×     $\frac{ 18}{5}$ km/hr

       Speed  =   135 km/hr  

The Speed of T1 is 135 km/hr.