A 2m wide car is moving uniformly with a speed of 8m/s along the edge of a straight horizontal road. A pedestriun starts to cross a road with a speed "v" when the car is 12 m away from him. The minimum value of v for the pedestrian to cross the road safety is ?

Question

ash2326 · Answer

There can be two cases, either the man crosses the road before the car reach him or he crosses it after the car has crossed

mathslover · Answer

well if we take the man to reach more safely there is that is the first case

ash2326 · Answer

see the diagram|dw:1361020408653:dw|
Time taken for car to reach the man, 
$$12 m\div 8 m/s= 1.5 seconds$$
In this time the man should cover the 2 meter distance, fairly simple now
Can you find v?

dls · Answer

|dw:1361020539994:dw|
@ash2326 just trying..i dont think there will be 2 cases,he should move making an angle theta with the axis not straight..