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Differential Calculus

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24 Aug 2011 02:23:46 IST

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aquestion from relative motion.....

Mathematics

at the instant the traffic light turns green, a car starts with a const. accln of 2m s^-2 . at the same instant a truck travelling with a const. speed of 10 m s^-1 ., overtakes nd passes the car. how far beyond the starting pointwill thd car overtake the truck????

a) 200 m

b) 100 m

c) 150 m

d) 50 m

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dhruv dharamshi

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24 Aug 2011 06:28:36 IST

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Take time to be common in the two cases and you will get your answer.

Yagyadutt Mishra

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Joined: 19 Feb 2009

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24 Aug 2011 09:23:09 IST

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When the car will overtake the truck ...following quantities will be same!

1) Both will travel the same distance from the starting point....because ultimately the car catches the truck..(let say h )

2) Both will travel for the same time because both are starting from at the same time .. ( let say t)

Applying equation for car !

Velcoity (initial) = 0
Acceleration = 2

SO , h = 0 + 0.5(2)(t)²
Hence h = (t)²

Now ...Apply the equation for the truck ..!

Since it travels with a constant velocity 10 , and upto time t hence the distance h will be

h = 10t
Compare both the equations ... 10t = t²

t = 10 sec..

And thus the distance will be 10*10 = 100 m

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