Questions tagged [spring]

An object such as a metal coil or air-filled tube which provides a force opposing the direction of deformation.

Filter by
Sorted by
Tagged with
37
votes
5answers
17k views

Slinky base does not immediately fall due to gravity

Why does the base of this slinky not fall immediately to gravity? My guess is tension in the springs is a force > mass*gravity but even then it is dumbfounding.
35
votes
6answers
146k views

Is the spring constant $k$ changed when you divide a spring into parts?

I've always been taught that the spring constant $k$ is a constant — that is, for a given spring, $k$ will always be the same, regardless of what you do to the spring. My friend's physics ...
32
votes
5answers
11k views

Why does my bumper scrape when driving fast over a bump but not slow?

When driving my car over a bump or a quick change in gradient (from flat to uphill or downhill to flat), if I don't drive slowly and the bump/change in gradient is large enough, I'll end up with my ...
29
votes
3answers
5k views

Stretch length of horizontal and vertical springs

If the spring in Figure A is stretched a distance d, how far will the spring in Figure B stretch? The spring constants are the same. The answer is "by half". I don't get it, to me it's the same.
28
votes
2answers
4k views

Why do my experimental data for Hooke’s law not match the expected data?

As we all know, force applied to a spring is directly proportional to the extension of spring as shown below: However, my experimental results for a simple spring from a school laboratory don't match ...
25
votes
8answers
9k views

Why is the potential energy of a spring the same when it is compressed and stretched?

I'm giving a high school lecture and I want to introduce the potential energy of a spring. My students have not learned the Hooke's Law and the notion of integral is too advanced. I'm really trying to ...
22
votes
1answer
10k views

Why don't they use springs as an energy source for cell phones?

I know they used springs for clocks way back in the day and now it's all lithium ion batteries. For reference, consider the Iphone that has a battery with a capacity of 5 Watt hours (18,000 joules). ...
21
votes
1answer
978 views

Why does a flat sheet roll back into a cylinder when having rolled it once?

For example, if you were to roll a piece of paper into the shape of a hollow cylinder and then try to return the paper to its original, flat shape, it would naturally roll to the cylinder when you let ...
20
votes
3answers
7k views

Is there a deep reason why springs combine like capacitors?

I was solving a practice Physics GRE and there was a question about springs connected in series and parallel. I was too lazy to derive the way the spring constants add in each case. But I knew how ...
19
votes
4answers
106k views

Why does a ball bounce lower?

If a ball hits the floor after an acceleration then why does it bounces lower? I mean the Energy is passed to the floor then why does the floor give back less Energy?
18
votes
5answers
4k views

How is potential energy actually stored in a steel spring at the atomic level?

Elasticity is one the most intriguing phenomena, wiki gives a summary explanation of what happens in a steel spring: the atomic lattice changes size and shape when forces are applied (energy is ...
17
votes
4answers
2k views

Will slinky length be different on the moon?

If we hold one end of a slinky and leave other end free, the earth's gravity applies force on the slinky and it expands. If we do the same on the moon with the same slinky, will the acquired height of ...
13
votes
3answers
6k views

How much work can a force on a spring do? (Why are two methods wrong?)

This was a question my friend found in a book. A block attached to a spring pulled by a constant horizontal force is kept on a smooth horizontal surface. Initially the spring is in its natural state. ...
13
votes
1answer
4k views

Can Hooke's law be derived?

Can we derive Hooke's law from the theory of elasticity? I know it is not a fundamental law and therefore can be derived from more basic considerations.
11
votes
4answers
2k views

Why can all solutions to the simple harmonic motion equation be written in terms of sines and cosines?

The defining property of SHM (simple harmonic motion) is that the force experienced at any value of displacement from the mean position is directly proportional to it and is directed towards the mean ...
11
votes
1answer
3k views

Understanding transverse oscillation in 1 mass, 2 spring systems

Lately I have been working through some nice problems on mass-spring systems. There are tons of different configurations - multiple masses, multiple springs, parallel/series, etc. A few possible ...
10
votes
2answers
2k views

Forget Hooke's law. Why does a spring exert a force?

Forgetting Hooke's law for a minute why, from a microscopic perspective (preferably quantum) on up to a macroscopic one, does a spring under tension exert a force? I was thinking that there might be ...
10
votes
4answers
13k views

Why does a spring lose its energy when compressed for a long time?

Why does a spring lose a part of its energy when compressed for a long period of time? Is it because the material gets bent?
10
votes
2answers
4k views

What will be different if the spring is not massless?

In almost all text, it uses the massless spring as example to illustrate the idea of elastic potential energy. I wonder what's really being changed if we consider the mass of the spring? I saw a ...
9
votes
2answers
6k views

Nonlinear spring $F=-kx^3$

A nonlinear spring whose restoring force is given by $F=-kx^3$ where $x$ is the displacement from equilibrium , is stretched a distance $A$. Attached to its end is a mass $m$. Calculate....(I can do ...
9
votes
3answers
890 views

How do we dampen a spring-mass system with respect to time?

Here https://en.wikipedia.org/wiki/Harmonic_oscillator we have an equation for displacement of a mass on a string as a function of time. ${\displaystyle x(t)=A\cos \left({\sqrt {\frac {k}{m}}}t\right)...
9
votes
2answers
312 views

What can be known about the formulas for energy only from the fact that it is conserved?

The question is to figure out how the energy can be derived knowing just one thing: There is a quantity called Energy that is conserved over time. The goal is to get an equation that somehow ...
9
votes
4answers
6k views

How far does a trampoline vertically deform based on the mass of the object?

If a baseball is dropped on a trampoline, the point under the object will move a certain distance downward before starting to travel upward again. If a bowling ball is dropped, it will deform further ...
9
votes
1answer
295 views

Motivating classical wave equation PDE

I'm teaching a geometry course covering spectral problems, using eigenvalues of the Laplace operator for shape analysis ("Can you hear the shape of a drum?"). I thought I'd cover where the wave ...
9
votes
1answer
495 views

What's the hooke's law in general relativity?

Now I'm trying to derive the hooke's law in general relativity,but I have many difficulties with it. First,I try to search google/google scholar.But I found nothing about the hooke's law in general ...
8
votes
6answers
28k views

Why does the acceleration $g$ due to gravity not affect the period of a vertically mounted spring?

For a vertically mounted spring, I was looking at the formula $ T= 2\pi \sqrt{m/k}$ for a period. Why doesn't the gravitational acceleration $g$ factor in?
8
votes
2answers
33k views

How much force is in a keystroke? (estimated, of course)?

I'm a software developer, and I need to calculate the estimated amount of force expended typing stored text. Preferrably in some interesting way. (i.e. the force exerted on keys thus far is enough to ...
8
votes
3answers
531 views

Potential energy of a spring vs potential energy of the spring-mass system

What is the difference between potential energy of a spring and potential energy of the spring-mass system? The reason I am asking this question is, is elastic potential energy a property of the ...
8
votes
3answers
389 views

Experimental Result Cannot Be Explained by Theory for 2 Spring 1 Mass System

We have 2 spring 1 mass system in 2D as shown, Here is my brief attempt of solution: $$\vec{F_x} = \vec{F_{1x}} + \vec{F_{2x}}= -k (x + l) \hat{\imath}- k (x-l)\hat{\imath} = -2 k x \hat{\imath} \...
8
votes
3answers
504 views

Potential energy of springs and gravity, and work of a force

I am currently really stuck on this problem and I am not sure how to actually solve it, I think I can reason it out logically but I do not know how to show it. Here it is and under I will show what I ...
8
votes
4answers
594 views

Newton's Third Law As Discussed in Den Hartog's Mechanics

A question, but some preliminaries in order to avoid answers involving concepts not yet introduced in the text I'm reading--Den Hartog's Mechanics. Near the very beginning of his book, Den Hartog ...
7
votes
6answers
3k views

How does cutting a spring increase spring constant? [duplicate]

I know that on cutting a spring into n equal pieces, spring constant becomes n times. But I have no idea why this happens. Please clarify the reasons
7
votes
4answers
2k views

What is the reason for this apparent paradox caused by a massless spring with a locking mechanism?

Imagine that a ball of mass $m$ is launched at a block, which also has mass $m$. Attached to the block, facing the ball, is a massless spring with a massless board at the end. Alternatively, we can ...
7
votes
6answers
2k views

Springs with some finite mass

Let us consider a spring which is having some finite mass. By the help of some external agent the spring has been extended by some distance $x$. Will the restoring force produced in the spring still ...
7
votes
2answers
2k views

Forced harmonic oscillator with two springs

Consider a vertical system of two springs in series, with a mass(50 g) between them. From below the system is driven by a vibration generator. The setup is shown here, but the picture is taken while ...
7
votes
1answer
505 views

Finding coefficient of proportionality

Recently in my AP Physics class I did a lab in which I measured k for a spring by setting up an oscillating system with it, and timing the period, repeating for different masses. Since $T=2\pi\sqrt{\...
7
votes
3answers
2k views

Center of mass of heavy spring

If a heavy spring of uniform density and mass $m$ is hung vertically so that it is stretched by gravity under its own weight, where is the center of mass? I have had a few people tell me it is 1/2 ...
7
votes
3answers
1k views

Do two springs compressed springs placed against each other obey Newton's third law?

I've been mulling over the following scenario. Say I take two springs whose force is given by some well-defined function of position (for example, Hooke's law F=kx will do). Using this law, I choose ...
6
votes
8answers
429 views

Doesn't the work $W = \int F \, dx$ count only the work done by the outermost point of a spring?

When we use the integral to calculate the work done by the spring force, then according to my interpretation, we are only calculating the work done by the outermost point on the spring. Why don't we ...
6
votes
2answers
183 views

How come the formula $W=Fd$ doesn't apply for energy stored in springs?

I always thought that work is like the energy transferred and it is given by $W=Fd$, but this concept gets problematic for springs. If the force $F$ is applied to a spring which compresses it by a ...
6
votes
2answers
29k views

Two masses attached to a spring

I'm trying to understand the solution of the following problem. Two masses $m_{1}$ and $m_{2}$ slide freely in a horizontal frictionless track and are connected by a spring whose force constant is $...
6
votes
3answers
1k views

How does the shape (form; not cross-section) of a spring impact performance?

Cylindrical compression springs are everywhere and then some applications choose other forms like rectangular or unique polygonal form. What impact does the form of a compression spring have and how ...
6
votes
1answer
2k views

Lagrangian of a 2D double pendulum system with a spring

In the figure above (please excuse my Picasso drawing skills), we have the general 2D double pendulum system with a slight modification, there's a spring connecting the masses instead of the usual ...
6
votes
1answer
1k views

Kinetic energy of a massive spring

Suppose we had a spring-mass system where the spring isn't assumed to be massless (has mass $M$) and is of length $L$. One end of the spring is held fixed and the other end I guess is left to freely ...
6
votes
3answers
18k views

What factors influence the spring constant?

For certain springs we have been taught that Hookes law, $F=-kx$ works. For such springs, what factors determine k. For instance, k is proportional to length. Can k be expressed in terms of dimensions,...
6
votes
1answer
5k views

Effective mass in Spring-with-mass/mass system

Suppose you have a particle of mass $m$ fixed to a spring of mass $m_0$ that, in turn, is fixed to some wall. I'm trying to calculate the effective mass $m'$ that appears in the law of motion of the ...
6
votes
3answers
3k views

Equivalent spring-constant for infinite square grid of springs

Consider an infinite square grid, where each side of a square is a spring following Hooke's law, with spring constant $k$. What is the relation between the force and displacement between two points? ...
6
votes
2answers
979 views

Mass hanging from spring in free fall

Q: A mass $m$ hangs from a massless spring connected to the roof of a box of mass $M$. When the box is held stationary, the mass-spring system oscillates vertically with angular frequency $\omega$. If ...
6
votes
2answers
426 views

Nonuniform acceleration due to rubber rope

What I want: I have a rubber rope which is $5m$ in length when not stressed and is able to stretch about $100\%$ (to $10m$ long). I want to accelerate a constant mass horizontally, which has ...
5
votes
2answers
661 views

In a four mass six spring vibration, how is the kinetic energy represented

This is from Hobson, Riley, Bence Mathematical Methods, p 322. A spring system is described as follows (they are floating in air like molecules): The equilibrium positions of four equal masses M of a ...

1
2 3 4 5
21