Using the Work-Energy Theorem, you can determine how the stopping distance
is related to the car's initial velocity:
W = KE
fd = 0.5mv2
mmgd = 0.5mv2
mgd = 0.5v2
If we assume the brakes "lock" the wheels to create a skid mark, then the
above result shows that the stopping distance does NOT depend on the car's
mass.
However, students tell me and Driver Manuals often state that the weight
of the vehicle IS a factor (heavier = longer stopping distance). In the
above calculation, I am dealing with an idealized case, but in "real-life"
anti-lock brakes change the actual stopping distance depending on the
weight of the vehicle. I've also heard that large trucks have a unique
braking system. Can anyone elaborate on these ideas?