Question

You are driving along a straight road at night at a constant speed of 26.5 m/s

when
you see a stalled car 75.2 m ahead. It will take you 0.75 seconds to react,
and then you will slam on your brakes, skidding to a halt in a time of 4.85
seconds. What would your total stopping distance be, from the moment you first
see the stalled car? What does this imply about whether you will hit the stalled
car or not?

Answer 1

84.1 m

Step-by-step explanation:

Δx = stopping distance = Vot + 1/2at²

find a (acceleration first):

a = ΔV/t = (0 - 26.5 m/s)/4.85 s = 5.46 m/s²

Δx = (26.5 m/s)(0.75s) + (1/2)(5.46 m/s²)(4.85 s)²

Δx = 19.9 m + 64.2 m = 84.1 m

You will hit the car! During the 0.75 s reaction time, you've already gone 19.9 m, then you need another 64.2 m to come to a complete stop.