Question

A subway train starts from rest at a station and accelerates at a rate of 1.60 m/s2 for 14.0s. It runs constant speed for 70.0s and slows down at a rate of 3.50 m/s2 until it stops at the next station find the total distance covered.

Answer 1

The total displacement is the sum of d1+s2+d3, where

d1d1=.5*1.6*14^2
we also need v1=1.6*14

d2=v1*70

d3=v1*t2-.5*3.5*t2^2
where
0=v1-3.5*t2



d1=156.8 m
v1= 22.4 m/s

d2=1568 m

t2=6.4 seconds

d3=71.68 m

total distance is 1.8 km

Answer 2

i think he's right