A car is moving with speed of 150 km h - 1 and after applying the brake it will move 27 m before it stops. If the same car is moving with a speed of one third the reported speed then it will stop afte

Question

A car is moving with speed of 150 km h - 1 and after applying the brake it will move 27 m before it stops. If the same car is moving with a speed of one third the reported speed then it will stop after travelling _____ m distance.

TestHub · Accepted Answer

In both cases, the final velocity is zero. Using equation of motion for constant acceleration
$v^{2} = u^{2} + 2 a s$
$\Rightarrow 0^{2} - u^{2} = - 2 a (27) ... (1)$
$\Rightarrow 0^{2} - {(\frac{u}{3})}^{2} = - 2 a s^{'} . . . (2)$
From $(1)$ and $(2)$ ,
$2 a (27) = 9 (2 a s^{'})$
$\Rightarrow s^{'} = 3 m$

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