• Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.


New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback


(propose a free ad)

Site Statistics

162 submissions , 131 unreviewed
4,212 questions , 1,579 unanswered
5,032 answers , 21,376 comments
1,470 users with positive rep
597 active unimported users
More ...

  Max induction of spring with two colliding trains

+ 0 like - 2 dislike

Two trains collide, train A weights 15.000 kg and moves with 10km/u (2.77... m/s) to the right, the other train weights 30.000kg and moves with 20km/u (5.55m/s) to the left. Train A has a spring on its right side with k=3MN/m. What is the max induction of that spring?
I know it has something to do with T1 +V1 = T2 V2, but I'm confused because the spring is moving too.

Closed as per community consensus as the post is not graduate-level
asked Jan 30, 2018 in Closed Questions by anonymous [ no revision ]
recategorized Aug 26, 2018 by Dilaton

This is not graduate-level, voting to close. 500 rep users please upvote the closevote here.

1 Answer

+ 0 like - 0 dislike

Found it myself, First I had to look what the result of the two trains collision would be. (ma*va1+mb*vb1 = (ma+mb)*v2) and then I could fill in the T1 + V1 = T2 + V2 formula with T1 = 1/2*ma*va² + 1/2*mb*vb² and V1 = 0 since s1 of the spring is. And T2 = 1/2*(ma+mb)v2² and V2=1/2*k*smax².
Resulting in smax = 0.4809 meters.

answered Jan 30, 2018 by anonymous [ no revision ]

user contributions licensed under cc by-sa 3.0 with attribution required

Your rights