At the instant the traffic light turns green. a car that has been waiting at an intersection starts ahead with a constant acceleration of 3.20 m/s2. At The same instant a truck, traveling with a constant speed of 20.0 m/s, overtakes and passes the car. (a) How far beyond its starting point does the car overtakes the truck? (b) How fast is the car traveling when it overtakes the truck? (c) Sketch an ?x???t? graph of the motion of both vehicles. Take ?x? = 0 at the intersection. (d) Sketch a ?vx???t? graph of the motion of both vehicles.

Solution 34E Step 1 0f 4: 1 2 1 2 a) -x0=v t0x 2 axt gives x =T t a0T x = C 2 aCt x = x gives t=0 and v = 1 a t T C 0T 2 C 2 0T 2(20) And t= aC = 3.20 =12.5 s 1 1 At this t, T =v 0T20×12.5=250 m and x= 2 aCt = (2.20)(2.5)= 250 m So the car and truck have each travelled 250 m Step 2 0f 4: b)At t= 12.5 s, the car has v x v +oxt =(x.20)(12.5)=40 m/s