Question

019 10.0 points

An engineer in a locomotive sees a car stuck
on the track at a railroad crossing in front of
the train. When the engineer first sees the
car, the locomotive is 100 m from the crossing
and its speed is 12 m/s.
If the engineer's reaction time is 0.55 s,
what should be the magnitude of the mini-
mum deceleration to avoid an accident?
Answer in units of m/s².

Answer 1

Step-by-step explanation:

Distance remaining after reaction time

s = s₀ - v₀t

s = 100 - 12(0.55) = 93.4 m

v² = u² + 2as

a = (v² - u²)/2s

a = (0² - 12²) / 2(93.4) = - 0.770877944...

|a| = 0.77 m/s²