Need help with some acceleration problems (Deceleration-Stopping, Intercepting)?

Question

Just started Physics and the teacher never bothered to do much explaining so now I request help! I'm sure its not that complicated but it certainly is when you have no formula for the stuff. So could I get some help with these two problems?

1.) A car is traveling 16 m/s when the driver sees a child standing in the road. He takes 0.8 s to react, then steps on the brakes and slows at 6.5 m/s^2. How far does the car go before it stops?

2.) A car is traveling 28 m/s to the east, while a truck, initially 625 m away, is moving at 20 m/s to the west along the same road. Where do they meet?

Answer 1

1)

D = D1 + D2;  D1 = Vo*Tr = 16*.8 = 12.8 m; D2 = V²/(2a) = 16²/(2*6.5) = 19.69 m.  Ergo, D = 12.8 + 19.69 = 32.49 m

2)

The relative speed is 28+20 = 48 m/s, so t = D/Vr = 625/48 = 13.02 sec

Ergo, they meet 28*13.02 = 364.58 m from the initial position of the first car.  Check:  20*13.02 = 260.416 which when added to 364.58 = 625 m.