Asked by Sandy

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.

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?
Answered by oobleck
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...
Answered by oobleck
oops. t = 5.55 seconds
But I'm sure you caught that ...
Answered by Sandy
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?
Answered by Damon
since the acceleration is constant you can use the average speed
25 m/s for the 5.56 seconds
5.56 * 25 = 139 meters
Answered by henry2,
V^2 = Vo^2 + 2a*d = 0.
50^2 + (-18)*d = 0,
d =