v' = -22 ft/s^2,

so:

v = -22t +v0

at t=0 v=50*5280/60^2 ~= 73.33 ft/s

Hence:

v = -22 t + 73.33

and the vehicle comes to a rest when v=0, that is when:

-22 t + 73.33 = 0,

or t = 3.33 s

now if x is the distanced travelled since breaking started then:

x' = v = -22 t + 73.33,

so:

x = -11 t^2 +73.33 t + x0,

but x0=0, and at t= 3.33 s:

x = 122.21 ft

RonL