Question

Two cars leave with a time gap of 1 min from the same point. They move with an acceleration of 0.2m/s^2.how long after the departure of the second car does the distance between them become equal to three times its value , when the second car just starts?

Answer 1

It will take 1 min

Explanation:

car1 start from rest and drives 60 s => s = at²/2 = 0.5*60²/2 = 900 m

car 2 starts when car 1 has driven 900 m.

car 1 drives s1 = a(t + 60)²/2

car 2 drives s2 = at²/2

The diffence s1 - s2 = 3* 900 = 2700

a(t+60)²/2 - at²/2 = 2700

(t+60)² - t² = 5400/a

120t + 3600 = 5400/0.5 = 10800

t = (10800-3600)/120 = 60

Answer 2

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