A 15,000-kg train accelerates uniformly from 0 to 15 m/s when passing through a distance of 150 m.What is its kinetic energy when it is 75 m down the track?

Question

Quizplus · Accepted Answer

First, we need to find the train's initial velocity using the given distance and acceleration:

final velocity^2 = initial velocity^2 + 2ad

(15 m/s)^2 = 2a(150 m)

a = 1.5 m/s^2

Next, we can find the kinetic energy using the formula:

KE = 1/2mv^2

We know the mass is 15,000 kg and the velocity when the train is 75 m down the track is:

v^2 = 2ad

v^2 = 2(1.5 m/s^2)(75 m)

v = 27.39 m/s

KE = 1/2(15,000 kg)(27.39 m/s)^2 = 840 kJ

Therefore, the answer is C.

A 15,000-Kg Train Accelerates Uniformly from 0 to 15 M/s