Question

A driver of train travelling at 40 m/s applies the brakes as a train enter a station The train slows down at the rate of 2m/s The platform is 400 m long will the train stop in time

Answer 1

Given,
a = -2m/s²
u = 40m/s
s = 400m
v = 0 (as the train stops)

By applying s = ut + 1/2at²

400 = 40t - 1/2 × 2t²
t = 20 sec.

The train will stop in 20 seconds.