Question

Two motor cars starting off with a time gap of 2 minutes, travel in the same direction with the same acceleration. Time taken by the second car, since its departure, to complete (1/9)th of the distance covered by the first car is:

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Solution

The correct option is **B** 1 minute

Distance traveled by the first car:

s1=12at2

Distance traveled by the second car:

s2=12a(t−2)2

If t is the time taken by a car to move a distance s, then,

s1=12at2

Distance traveled by the second car:

s2=12a(t−2)2

Given: s2=s1/9

⇒12at29=12a(t−2)2

⇒12at29=12a(t−2)2

⇒(tt−2)2=9

⇒t=3min

∴ The time taken by the second car is 3−2=1 minute

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