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An automobile, travelling at 40km/h, can be stopped at a distance of 40 m by applying brakes. If the same automobile is travelling at 80 km/h, the minimum stopping distance, in metres, is |
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Answer» initial velocity ( u ) = 40 km/hr = 40 × 1000 m / 3600 s = 40 × 5 / 18 m/s = 200 / 18 m/s .FINAL velocity ( V ) = 0 m/sDistance ( S ) = 40 m .v² = u² + 2 a S= > 0 = u² + 2 a S= > ( 200 / 18 )² + 2 × 40 × a = 0= > 80 a = - 40000 / 324= > a = - 500 / 324When initial velocity = 80 km/hr = 80 × 5/18 m/s = 400/18 m/sv² = u² + 2 a S= > u² + 2 a S = 0= > ( 400 / 18 )² + 2 × - 500 / 324 × S = 0= > 1,60,000 / 324 - 1000 / 324 S = 0= > 1,6000 / 324 S = 40,000 / 324= > S = 1,60,000 / 1000= > S = 160 mANSWER :The distance WOULD be 160 m |
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