At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.3 m/s$^2$. At the same instant a truck, traveling with a constant speed of 9.8 m/s, overtakes and passes the automobile.
(a) How far beyond the traffic signal will the automobile overtake the truck?
(b) How fast will the car be traveling at that instant?
I have 83.51 for a, which is right.
I'm not sure how to solve b. I have v = a*t, then v = 2.3 * 83.51. It's not accepting that, though.
$$v_0t+\frac12at^2=Vt$$
$$t(1.15t-9.8)=0$$
$$t=196/23$$
$$v=v_0+at=2.3*\frac{196}{23}=19.60(m/s)$$