Passing of a train II

Classical Mechanics Level 2

A passenger train of length L 1 = 60 m L_1=\text{60 m} travels at speed of v 1 = 80 km/h v_1=\text{80 km/h} . How long (in seconds) does it take this train to pass a freight train of length L 2 = 120 m L_2=\text{120 m} traveling at a speed of v 2 = 30 km/h v_2= \text{30 km/h} in the same direction?

24.92 none 4.93 12.96 5.94

Chakravarthy B by chakravarthy b , 17, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Chew-Seong Cheong
Feb 26, 2019

Using relative velocity of 80 − 30 = 50 km/h 80-30 = 50 \text{ km/h} and considering the freight train to be stationary, then the passenger train need to travel 120 + 60 = 180 m 120+60 = 180 \text{ m} to pass the freight train. Therefore, the time taken is t = 180 50 × 1000 × 60 × 60 = 12.96 s t = \dfrac {180}{50 \times 1000} \times 60 \times 60 = \boxed{12.96} \text{ s} .

0 Helpful 0 Interesting 0 Brilliant 0 Confused

@chakravarthy b , it is so strange to see k m h \frac {km}h . I have never seen this in books. You can use \ ( ... \ ) with no space between backslash \ and the brackets () to effect LaTex. For example, \ (v_1 = 80 \text{ km/h}\ ) v 1 = 80 km/h v_1 = 80 \text{ km/h} .

Chew-Seong Cheong - 2 years, 3 months ago

Log in to reply

@Chew-Seong Cheong ok.

chakravarthy b - 2 years, 3 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...