Calculating Train Speed Increase: 1.5x10^7 kg Train

[Jordash]

Homework Statement

A frieght train has a mass of 1.5x10^7 kg. The wheels of the locomotive push back on the tracks with a constant net force of 7.5X10^5N, so the tracks push forward on the locomotive with a force of equal magnitude. (ignore aerodynamics and friction) how long would it take to increase the speed of the train from rest to 80km/h?

Homework Equations

The Attempt at a Solution

So far I was able to calculate the acceleration:

a=F/m

a=7.5*10^5/1.5*10^7

a=5*10^12m/s^2

am I going in the right direction and how would I proceed?

 

[needlottahelp]

I believe you are on the right track. You need to use one of the kinematics equation though to find the time.

 

[nlightner]

I would approach this problem by using the equation for acceleration, a=F/m, which you have correctly identified. From there, I would use the equation for average velocity, v=at, where v is the final velocity, a is the acceleration, and t is the time. In this case, we are looking for the time it takes for the train to reach a final velocity of 80 km/h, which we can convert to meters per second by multiplying by 1000/3600, giving us 22.22 m/s. Plugging in our known values for acceleration and final velocity, we get:

22.22 m/s = (5*10^12 m/s^2)t

Solving for t, we get t = 4.44*10^-12 seconds.

However, this answer may not be realistic as it does not take into account the limitations of the train's engine and the track's ability to withstand such high forces. It is important to consider the practicality and feasibility of the solution in addition to the mathematical calculations.