Question

Please Explain how to do this.
A train starts from rest and accelerates at a rate of 1.6m/s^2 for 10s. It runs at constant speed for 70s and slows down for a rate of 3.5m/s^2 until it stops. Find total distance covered.

Answer 1

Calculate velocity after 10s
v = u + at
v = 1.6*10 = 16m/s

Distance traveled in first 10 sec
s = ut + 0.5 at^2
s1 = 0.5*1.6*100 = 80m

Distance traveled with constant speed
s2 = 16 * 70 = 1120m

Distance traveled during braking
v^2 = u^2 + 2 as
0 = 256 - 2*3.5*s3
s3 = 36.6 m

Total distance is s1 +s2 +s3

Answer 2

Thanks shadowfax that looks right.