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A driver can stop his car from the red s...

A driver can stop his car from the red signal at a distance of 20 m when he is driving at 36 kmph and 41.25 m when he is driving at 54 kmph. Find his reaction time.

Text Solution

Verified by Experts

Let t is reaction time of driver during which he moves with uniform speed
Distance coverd during reaction time = `S_1` = ut
As he applies brakes, distance covered before coming to rest is `S_2=u^2/(2a)`
Total distance covered is `s=ut+u^2//2a`
`20=10t+100/(2a)` ...(1)
41.25=`15t+225/(2a)`...(2)
Solving above equations 3.75=7.5t
t=0.5s
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