Question

At the instant the traffic light turns green, an automobile starts with a constant acceleration a_x  of 6.0 ft/ s², at the same instant a truck, travelling with a constant speed of 30 ft/s, overtakes and passes the automobile. 

(a) how far beyond the straight point will automobile overtake the truck? 

(b) How fast will the automobile be travelling at that instant? (It is instructive to plot qualitative graph of x versus t for each vehicle.)

Answer 1

 Let it overtake after time t 

Distance travelled by truck = 30 t 

Distance travelled by automobile

It overtakes it at 300 ft distance. Its velocity is 60 ft s^-1 .