Two trains are moving in the same direction along parallel tracks. One of them is 200 m long travelling with a velocity of 20 m s- 1 . The second one is 800 m long travelling with a velocity of 7.5 m s- 1 . The time taken for the first train to overtake the second is

Question

Two trains are moving in the same direction along parallel tracks. One of them is 200 m long travelling with a velocity of 20 m s- 1 . The second one is 800 m long travelling with a velocity of 7.5 m s- 1 . The time taken for the first train to overtake the second is (A) 20s (B) 40s (C) 60s (D) 80 s

Tardigrade Admin · Accepted Answer

From the figure, the relative displacement is
Solution

s_{re l} = (800 + 200) m = 1000 m

(υ)_{re l} = (υ)_{1} - (υ)_{2} = (20 - 7.5) m s^{- 1}

= 12.5 m s^{- 1}

∴ t = \frac{s _{re l}}{υ _{re l}} = \frac{1000}{12.5} = 80 s

Q. Two trains are moving in the same direction along parallel tracks. One of them is $200 m$ long travelling with a velocity of $20 m s^{- 1}$ . The second one is $800 m$ long travelling with a velocity of $7.5 m s^{- 1}$ . The time taken for the first train to overtake the second is

$20 s$

$40 s$

$60 s$

$80 s$

From the figure, the relative displacement is

$s_{re l} = (800 + 200) m = 1000 m$
$(υ)_{re l} = (υ)_{1} - (υ)_{2} = (20 - 7.5) m s^{- 1}$
$= 12.5 m s^{- 1}$
$∴ t = \frac{s _{re l}}{υ _{re l}} = \frac{1000}{12.5} = 80 s$

Q. Two trains are moving in the same direction along parallel tracks. One of them is 200m long travelling with a velocity of 20ms−1 . The second one is 800m long travelling with a velocity of 7.5ms−1 . The time taken for the first train to overtake the second is

20s

40s

60s

80s