OnlineCBT
Physics · MOTION IN A STRAIGHT LINE
हिन्दीA car moving along a straight highway with a speed of \( 126\text{ km/h} \) is brought to a stop within a distance of \( 200\text{ m} \). What is the magnitude of retardation of the car and how long does it take to stop?
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Correct answer · Option B
\( 3.06\text{ m/s}^2 \text{ and } 11.43\text{ s} \)
Explanation
\( u = 126 \times \frac{5}{18} = 35\text{ m/s} \), \( v = 0 \), \( s = 200\text{ m} \). \( v^2 = u^2 + 2as \implies 0 = 35^2 + 2a(200) \implies a = -3.0625\text{ m/s}^2 \). Retardation = \( 3.06\text{ m/s}^2 \). Time \( t = \frac{v - u}{a} = \frac{-35}{-3.0625} = 11.43\text{ s} \).
