Question

*HELP PLZ IT'S DUE IN 2HRS*
If a train is at rest, when it accelerates at 1.4 m/s2 for 7 seconds.


What would the magnitude of the train’s displacement be?

Answer 1

Since train starts from rest,

=> Initial velocity = u= 0 m/s

Given,

• acceleration = a = 1.4 m/s²

• time = t = 7 seconds

Let us assume that the train moves in a rectilinear motion,

Thus in a straight line, Displacement = Distance covered = 's'

Using, second law of motion,

$s = ut + \frac{1}{2}a {t}^{2} \\ = > s = 0 \times 7 + \frac{1}{2} \times 1.4 \times {7}^{2} \\ = > s = \frac{1}{2} \times 1.4 \times 49 \\ = > s = \frac{1.4}{2} \times 49 \\ = > s = 0.7 \times 49 = 34.3m$

Thus, Displacement = 34.3 meters