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A car , moving with a speed of `50 km//hr` , can be stopped by brakes after at least ` 6m `. If the same car is moving at a speed of `100 km//hr`, the minimum stopping distance isA. `12 m `B. `18 m`C. `24 m`D. ` 6 m` |
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Answer» Correct Answer - C Case - 1 : ` u = 50 xx (5)/(18) m//s`, `v = 0 , s = 6m , a = a` `v^(2) - u^(2) = 2as rArr 0^(2) -(50 xx (5)/(18))^(2) = 2 xx a xx 6` `rArr -(50 xx (5)/(18))^(2)` = 2 xx axx 6` …(i) Case - 2: `u = 100xx5/18 m//sec, v = 0 , s = s, a =a ` `:. v^(2) -u^(2) = 2as ` `rArr 0^(2)-(100xx5/18)^(2) = 2as ` `rArr -(100xx5//18)^(2) = 2 as` ...(ii) Dividing (i) and (ii) we get ` (100xx100)/(50xx50) = (2xxaxxs)/(2xxaxx6) rArr s = 24 m ` |
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