A truck is travelling along a straight road at a constant velocity of 50ms^-1 and sees a dog 200-metres away. In an attempt to avoid an accident, the driver has to brake to a sudden stop.

Question

Once the brakes are applied, the truck now has an acceleration of -9.0ms-2. How far does the truck travel when coming to a stop after the driver applies the brakes?

Answer 1

v = 50-9t, so it takes 5 seconds to stop
s = 50t - 4.5t^2
So, plug in t=5 and discover the fate of the dog, who has stupidly stood there for 5 seconds in front of an oncoming truck...

Answer 2

oops. t = 5.55 seconds
But I'm sure you caught that ...

Answer 3

What total distance does the truck travel from when the driver notices the danger to when it comes to stop? does the truck hit the dog?

Answer 4

since the acceleration is constant you can use the average speed
25 m/s for the 5.56 seconds
5.56 * 25 = 139 meters

Answer 5

V^2 = Vo^2 + 2a*d = 0.
50^2 + (-18)*d = 0,
d =