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A motor car of width w moves uniformly along a straight road , parallel to the pavement...
A motor car of width w moves uniformly along a straight road , parallel to the pavement almost touching it. A pedestrian on the edge of the pavement at a distance l ahead of the car begins to walk uniformly to cross the road . If v is the speed of the car and u is the speed of the pedestrian relative to the road , show that the pedestrian can cross the road safely in front of the car if
`u gt v sin (alpha)` , where `alpha = tan^-1 (w/l).`
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High School Teacher
Let A be position of the car and B is position of the man.The distance between A and B is I (given).Let B' is point on the opposite side of the point B.Let man crosses road by making an angle `alpha` with BB' and reaches point C .Thus
``Since `0<=alpha<=pi/2` ,therefore
Posted by aruv on August 16, 2013 at 5:17 PM (Answer #1)
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