Question

A train starts from rest and accelerates uniformly, until it has traveled 3.7 km and acquired a velocity of The train then moves at a constant velocity of for 410 s. The train then slows down uniformly at until it reaches a halt. What distance does the train travel while it is slowing down?
6.6 km

6.9 km

5.6 km

6.3 km

5.9 km

Answer 1

Correct Answer: Option B

The complete question is:
A train starts from rest and accelerates uniformly until it has traveled 3.7 km and acquired a velocity of 30m/s The train then moves at a constant velocity of 30m/s for 410 s. The train then slows down uniformly at  0.065m/s² until it reaches a halt. What distance does the train travel while it is slowing down?

We have the initial velocity u = 30 m/s
Final velocity = v = 0
Acceleration = a = -0.065 m/s²
The negative sign indicates that the train is slowing down.

Using the 3rd equation of motion, we can find the distance covered by the train:

2as = v² - u²
2(-0.065)S = 0 -30²
⇒
S = 6923 meters = 6.9 km