Question

Light-rail passenger trains that provide transportation within and between cities speed up and slow down with a nearly constant (and quite modest) acceleration. a train travels through a congested part of town at 7.0 m/s . once free of this area, it speeds up to 14 m/s in 8.0 s. at the edge of town, the driver again accelerates, with the same acceleration, for another 16 s to reach a higher cruising speed. what is the final speed?

Answer 1

First let us calculate the acceleration.

v1 = v0 + a t1

where v1 is final velocity, v0 is initial velocity, a is acceleration and t is time

Calculating for a:

14 m/s = 7 m/s + a * 8 s

a = 0.875 m/s^2

 

Therefore the final speed is calculated similarly:

v2 = v1 + a t2

v2 = 14 m/s + (0.875 m/s^2) * 16 s

v2 = 28 m/s