Question

A truck is moving forward at a constant speed of 20m/s.The driver sees a car at a distance of 110m stopping suddenly. After a reaction time he applies the brakes which give the truck an acceleration of -3m/s^2. What will be the maximum allowable reaction time to avoid a collision and the truck would have moved before the brakes take hold?

Answer 1

u = 20m/s
v = 0m/s
a = -3m/s²

s = v² - u² /2a
s = 0-400/-6
s = 400/6 = 66.67m

Let a be x and distance be 110m

2as = v² - u²

a = -400/220
a = -1.8m/s²

v = u + at
0 = 20 + (-1.8t)
t = 20/1.8 = 11.1s

Answer 2

Answer:

Here is the answer

Explanation:

time = 11.1 seconds.