A car moving with a speed of 40 km/h can be stopped by applying brakes after at least 2m. If the same car is moving with a speed of 80 km/ h. The minimum stopping distance will be……………..

A car moving with a speed of 40 km/h can be stopped by applying brakes

1.	A car moving with a speed of 40 km/h can be stopped by applying brakes after at least 2m. If the same car is moving with a speed of 80 km/ h. The minimum stopping distance will be……………..
Answer» 8 2 4 6 Solution :Stopping distance `ds = (v ^(2))/(2d) ""…(1)` Here, `v _(1) = 40 km//h = 40 xx (5)/(18) = 11 m //s and ds _(1) = 2m` is given. `therefore 2 = ((11) ^(2))/( 2A _(1))` (From eq. (i)) `therefore 4A =121` `therefore a _(1) = 30 ms ^(-1)` Now, same CAR is there, so `a _(1) =a_(2) =a.` `therefore v _(2) = 80 km//h =8- xx (5)/(18) ~~22m//s and a _(1) =a_(2) =30 ms ^(-1) ,So, ds _(2) = ?` `therefore ds _(2) = ((22) ^(2))/(2 xx 30 )= (484)/(60) ` `therefore ds _(2) = 8m`