nanogrinder

sorry about that. p.s. krz i forgot to add in the second it took for the officer to react.

i got 14.8 first i took 90km/h and 140km/h then converted them to m/s which comes out to be 25m/s and 38.9m/s respectively. we will call the car 25,x and car 38.9, z after this i use the equation d=Vot+.5at² where d=distance, Vo=original velocity, a=acceleration, t=time the first second for car x travels 25m, using d=25(1)+.5(0)(1²) the last part is zeroed out because there is no acceleration. car z travels 38.9m, d=38.9(1). we need to now make two equations involving car x and z that are set equal to each other,but we must also add in those other two answers in them. since they are going to be at an equal distance in a certain amount of time, we can do this 38.9t+38.9= 25+25t+.5(2)t² (btw we had to add the other values 38.9 and 25 into the equation) now get everything to one side -t²+13.9t+13.9=0 now just put the numbers into the quadratic formula then volia 14.8s i hoped that help explain, its hard to get these kinds of points across on the net.