All Questions
42
questions
-1
votes
1
answer
19
views
Strain energy stored in a bungee cord pulled at its midpoint [closed]
A bungee cord that behaves elastically has an unstressed length $L=.76$ m and a stiffness $k=140$ N/m. The cord is attached to two pegs, distance $b=.38$ m apart, and pulled at its midpoint by a force ...
0
votes
1
answer
37
views
What are the points to note in a spring+block system? [closed]
This is the solution to a question related to spring+block system, and I have some doubts regarding the concept behind this question
The solution reads
The velocity of the block increases till the ...
- 91
1
vote
1
answer
130
views
Why can we ignore the work done by gravity?
I am working through the problem above, starting with part (d). By the conservation of energy setting the spring in equilibrium as $y_0$ as the difference in length of the unstretched spring to the ...
1
vote
2
answers
219
views
Lagrangian function of a mass-spring-system with deflections in 2D [closed]
I’m looking for the lagrangian function of the following problem (as seen in the picture). We have a mass connected to two springs. We can deglect the mass in two dimensions.
My main problems are:
...
- 11
0
votes
1
answer
93
views
Potential energy involving both elastic and gravity
A block of mass $m$ is placed against an ideal spring as shown. Initially the spring (of force constant $k$) is compressed by a distance $s$. The block is then released and slides a distance d up the $...
0
votes
1
answer
22
views
Finding the spring constant and magnitude of acceleration when it is dropped with the top attached to a ceiling [closed]
I've tried finding the potential energy by using PE = mgh then using PE = 1/2kx^2 to find k and setting PE = KE to find PE using velocity but neither is correct when finding the spring constant. I don'...
- 3
1
vote
1
answer
26
views
Right displacement in spring potential energy [closed]
I have a doubt in general, the above problem is an example.
Here , the elastic string can be treated as a spring and we know the potential energy of a spring is $\frac{1}{2} k (x_f-x_i)^2$
So , ...
- 11
0
votes
1
answer
112
views
Potential Energy of a Lagrangian System Involving a Mass and Spring [closed]
If you were to calculate the potential energy term of the Lagrangian for this system, would there be an mg term included, or would it be unnecessary as the change in potential energy of the mass would ...
- 3
0
votes
1
answer
148
views
Particle in a cylinder with a spring, sign convention in potential energy (Lagrangian multipliers)
I'm trying to get the force of constraint. The problem I have is when defying the sign of the potential energy using cylindrical coordinates $(\rho,\phi,z)$, what I have is:
$$
V=mgy-\frac{1}{2}k\left(...
- 7
0
votes
1
answer
569
views
Potential energy of a mass bewteen two springs with pendulum hanging [closed]
I need some help with this problem.
A particle of mass $m_1$ hangs from a rod of negligible mass and length $l$, whose support point consists of another particle of mass $m_2$ that moves horizontally ...
- 103
0
votes
1
answer
188
views
Elastic potential energy during elastic collisions
While working with problems on elastic collisions, I have come across this observation, that the elastic potential energy of a two-body system is the maximum when the relative velocity equals zero. In ...
- 1,638
0
votes
2
answers
423
views
Work-Energy Theorem, conservation of energy, and Elastic Potential Energy problem [closed]
So I'm having some trouble with this problem can anyone help me out on how to solve it?
A 3.0 kg block is released from rest at the top of a 3.4 m high frictionless incline. At the bottom of the ...
3
votes
3
answers
2k
views
How to calculate the potential energy of coupled oscillators?
The equations of motion that describe the above situation is given by:
$$ m \ddot{x_1} = -2kx_1 + kx_2 $$
$$ m \ddot{x_2} = -2kx_2 + kx_1 $$
Now I want to work out the potential energy of this system. ...
- 67
4
votes
3
answers
677
views
In this problem, why is the work done by the spring not equal to the line integral of the spring force over its displacement?
Problem statement:
In the given figure, two blocks A and B, each having a mass of 320 grams are connected by a light string passing over a smooth light pulley. The horizontal surface on which block A ...
- 556
0
votes
1
answer
60
views
What is the potential energy of the spring? [duplicate]
What is the potential energy of the spring?
On the left side there is a gravitational force $mg$ acts on the spring, same on for the right side. So, If force $mg$ streches the spring $x$ units then $...
- 699
0
votes
1
answer
101
views
To consider or not to consider potential energy of a mass attached to a spring in oscillation? [closed]
For the above system I have the following expressions for kinetic and potential energy:
$$
V = \frac{1}{2}\,k\,x^{2}+m\,g\,l\,(1-cos\,\theta)-m\,g\,x\\ T = \frac{1}{2}\,m\,\dot{x}^{2}+\frac{1}{2}\,m\,...
- 3
3
votes
2
answers
108
views
Why do we include $x$ in this Spring Equation?
I am currently in Physics 1 and we are learning about Energy. This may sound like a dumb question but I am currently trying to understand this. Here is the question of the problem:
A 10kg block is ...
1
vote
1
answer
4k
views
Potential energy of a mass-spring system
I'm having trouble with determining the potential energy of the mass-spring system depicted below. We assume that the extensions of all 3 springs are zero when $x_1=x_2=0$. The potential energy that I ...
- 192
1
vote
0
answers
98
views
Potential energy stored by an elastic circular loop on deformation to an ellipse
This question is related to an origami circular loop that I built. This structure is elastic and I intend to find the elastic potential energy stored by it when I deform it to an ellipse.
My actual ...
-1
votes
1
answer
143
views
Spring-mass problem [duplicate]
Question: A spring-mass system hangs vertically from a fixed support. The natural length of the spring is l. The block is displaced from the equilibrium position and constrained to move horizontally. ...
-2
votes
2
answers
481
views
In this question of elastic potential energy, why doesn’t the answer of compression come negative? [closed]
A smooth curved track terminates in a smooth horizontal part. A spring of spring constant $400N/m$ is attached at one end of a wedge fixed rigidly with the horizontal part. A $40g$ mass is released ...
- 153
-1
votes
1
answer
412
views
How to derive spring potential formula from Hooke's law?
I found this answer in another forum:
\begin{align}
W&=\int \mathbf F\cdot {\rm d}\mathbf x \\
&=-\int_0^xkx\,{\rm d}x \\
&=\frac{1}{2}kx^2
\end{align}
I don't understand why we have to ...
- 11
0
votes
2
answers
2k
views
Question regarding bungee jumper [closed]
A man who does bungee jump jumps by the platform. The mass of the man is 60Kg . There is 45m from the platform to the water. Without stretching the rope is 25m long. The spring constant(k)=160Nm-1. ...
- 222
0
votes
2
answers
2k
views
Getting 2 different answers when finding spring constant $k$ when gravity is involved
OK, so I've been wracking my brain for the past hour trying to figure out how to calculate k in a problem like this:
A mass of 10 kg is attached to a spring hanging from the ceiling. It is released,...
1
vote
2
answers
3k
views
Hanging mass from spring/ Setting potential to 0
I'm working a problem from Taylor's Classical Mechanics Book, and it's highlighted a couple issues I never quite wrapped my head around (despite getting good marks in advanced undergrad mechanics and ...
- 171
1
vote
1
answer
315
views
Finding the spring compression length for an object to reach $U = 0$ [closed]
I have a question on the following, pertaining to only parts c and d (b was shown to provide the mass of the asteroid and radius):
-
I'm going to define the mass of the asteroid here as $M_A$ and ...
- 3,200
-2
votes
2
answers
1k
views
Question related to Potential Energy - Mass Spring System [closed]
The P.E stored by a mass spring system at an extension of 2cm is 10J. The P.E stored by the same system at an extension of 4cm will be?
Someone please provide an extensive answer if possible.
- 1
0
votes
2
answers
4k
views
Potential energy of an Atwood Machine [closed]
The two weights on the left have equal masses $m$ and are connected by a massless spring of force constant $k$. The weight on the right has mass $M=2m$, and the pulley is massless and frictionless. ...
- 171
-2
votes
2
answers
3k
views
How to solve a spring question?
What is the difference between the distance a spring is stretched using $F=kx$ formula vs the distance using the work formula? They seem to give different answers.
Doesn't distance stretched using ...
- 823
-1
votes
1
answer
1k
views
Maximum height mass attached to a vertical spring with conservation of energy
There are various methods to find anything we like for a mass attached to a vertical spring, however I wanted to use the conservation of energy.
Suppose $m$ hangs from the spring of normal length $l$ ...
- 247
0
votes
2
answers
3k
views
Why is the work done on a spring obeying Hooke's Law $(1/2) F x$ and not $(1/2) Fx^2$?
The answer to the question is shown as B, whereas I believe it should be C. Why is this so?
- 21
1
vote
3
answers
2k
views
Difference in elongation in spring if it is stretched gradually and suddenly?
A spring is hanging vertically with a mass attached to it . Gradually lowered mass stretches the spring by $x$ m . If same body attached to the same spring is released suddenly, the maximum stretch in ...
- 135
2
votes
2
answers
731
views
Energy Stored in Spring [closed]
Area Z represents the energy stored in the spring when it is stretched to a length L
I am trying to understand why this is so:
$$E = \frac{1}{2}kx^2$$
Here, $x$ is the vertical side of triangle $Y$....
0
votes
2
answers
181
views
Working with the problems related to potential energy [closed]
Consider a spring mass system. A block is attached to a light vertical spring which is stretched under the load of block and this system is at a height $h$ from the ground.
Now my problem is that what ...
- 105
1
vote
2
answers
846
views
Elastic potential energy and equilibrium position when mass changes in vertical mass-spring system
I'm a bit stuck with this situation:
Suppose that an object $A$ with mass M=8 kg at 10 mt above the floor falls from rest tied to an 2 mt elastic rope, which does not exert any force since $A$ falls 2 ...
- 21
0
votes
2
answers
2k
views
Potential Elastic Energy between two carts [closed]
I have a problem in which two carts are attached by a compressed spring. I have found that cart $A$ moves at $1.1~\mathrm{m/s}$ to the right and has a mass of $0.39 ~\textrm{kg}.$ Cart $B$ has a mass ...
- 101
0
votes
1
answer
399
views
Spring Potential Energy [closed]
A spring whose spring constant is $k$, having an initial "free" length is $l$, is being pressed by $2$ hoops on a metal(the parabola) on his both sides. (see image below)
I want to calculate the ...
- 185
0
votes
2
answers
1k
views
Does really a spring compresses placed between two blocks when one block is given force on a frictionless surface?
When Spring is placed between two bodies on a frictionless surface it gets compressed when one block is given kinetic energy as told by my physics teacher. But it should not compress as there's no ...
0
votes
3
answers
4k
views
Hooke's law vs. elastic potential energy
I am currently learning about elastic potential energy and this is a question that was given to us by my teacher:
When a 13.2-kg mass is placed on top of a vertical spring, the spring compresses 5....
- 179
8
votes
3
answers
572
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 ...
- 81
1
vote
1
answer
773
views
Hooks Law and acceleration [closed]
A 435 gram sharpened piece of iron rebar into a spring loaded device. It
takes a force of 355 Newtons to compress the spring by 27.5 cm. With what speed does the
rebar shoot out of the device?
...
1
vote
2
answers
622
views
Using an electric winch to compress a spring and launch an object
I'm having trouble grokking the relationship between a winch's pull/torque and a spring's potential energy.
I would like to compress a spring using an electric winch and figure out how far it will be ...
- 13