Understanding the Relationship Between a Compressed Spring and Attached Wall

[andyrk]

Because science is complicated. Even the basics science are MUCH more complicated than many people think.

Also I was just thinking, does science come naturally to those who are good at it? Like I have been doing this for the past 3 years now and I don't enjoy doing this much and have to put a lot of effort to get things clear. But that's not the case with everyone right? Ofcourse I have gotten better, but after a LOT of effort.

It's not true. I don't know why you think it is.

Intuition.

 

[Drakkith]

Also I was just thinking, does science come naturally to those who are good at it?

I certainly true that science concepts are easier to grasp for some than it is for others. But so what? So is everything.

Like I have been doing this for the past 3 years now and I don't enjoy doing this much and have to put a lot of effort to get things clear. But that's not the case with everyone right? Ofcourse I have gotten better, but after a LOT of effort.

What have you been doing for the past 3 years? Have you been going to classes to learn science, or just read about things online, or what?

Intuition.

Your intuition is wrong. If you apply a force of 100 Newtons to the left end of a massless spring with a spring constant of 100, the force on the right side of the spring, which is anchored to the wall, starts at zero and reaches -100 Newtons once the left end of the spring has moved 1 meter. This is in accordance with the spring equation F = -kx.

 

[andyrk]

I think its problematic for me because it isn't as flexible as maths/programming. I am programmer/mathematician by field of study. Physics doesn't have that much creative potential in it.

 

[Drakkith]

I'm not sure I agree. Every programming language has certain rules that MUST be obeyed, else you can't use the language. As does math. I think the difference is that those rules are MUCH easier to learn and apply than the rules of science are (at least the programming rules are). Once you learn the rules, then you have a near infinite way of applying them.

If you haven't learned the most basic rules of physics, such as Newton's laws, which includes how to use them, then of course you're going to have trouble when you try to get into the details of more advanced topics.

 

[andyrk]

Correct. My bad.

 

[sophiecentaur]

So just applying a force on one end doesn't mean that the spring would extend or compress?

Of course not. If you apply a force to just one end, the spring will move off in the direction of the force and, if it is an ideal, massless spring, it will not compress at all. Things would be more complicated due to the distributed mass of a real spring. But - one thing at a time, I advise.

If I take a spring in my hand and stretch it a length x more than its original length, with both my hands. Now, do both my hands experience an inward force F=−kxF = -kx?

Yes. And the work done would be divided between the two hands, which would 'share' the displacement.

 

[Dale]

if the spring is mass-less, then unequal forces at its two ends can never lead to any compression/expansion of the spring. Why is this true?

Anything massless must have a net force of 0, otherwise it would have infinite acceleration per Newton's 2nd law. Is that clear?

 

[sophiecentaur]

I think its problematic for me because it isn't as flexible as maths/programming. I am programmer/mathematician by field of study. Physics doesn't have that much creative potential in it.

If you think Maths and Programming are "flexible" then try doing the wrong operation in Maths or Programming at any time and you will find you get the wrong answer out. It strikes me that you are trying to approach Physics (in nearly all of your recent threads), expecting it to be 'flexible' and you are just getting upset because it is, in fact, a discipline and not just a bit of chatty fun.
As for "creative potential", the advances that have been made in Physics over the centuries demonstrate a lot of creative potential from leading edge Physicists. But, in addition to their creative potential, they have been prepared to learn the basics with hard personal effort and self discipline. If you want to use your own personal creative potential in a less demanding study, there are many other fields that can give satisfaction with less personal intellectual input.
Physics is Hard.

 

[andyrk]

Anything massless must have a net force of 0, otherwise it would have infinite acceleration per Newton's 2nd law. Is that clear?

Yes. That much is clear.

 

[Dale]

Yes. That much is clear.

So the net force on the spring must be zero, and therefore the forces on either side of the spring must be equal and opposite. Otherwise they would not sum to zero.

Edit: thread closed. If you have further questions please show some effort working through the analysis first.