This tag is for the classical concept of forces, i.e. the quantities causing an acceleration of a body. It expands to the strong/electroweak force only insofar as they act comparable to ‘classical’ forces. Use [tag:particle-physics] for decay channels due to forces and [tag:newtonian-mechanics] or ...
1
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0answers
47 views
Fading transition and rotation of and object in 2D
I'm looking for sources about I guess dynamics subject.
The model I'd like to solve is reduced to a question of:
How does a force applied on a certain point of an object results in both fading ...
7
votes
3answers
546 views
Is the normal force a conservative force?
Most of the time the normal force doesn't do any work because it's perpendicular to the direction of motion but if it does do work, would it be conservative or non-conservative?
For example, consider ...
0
votes
1answer
156 views
If 2 charges have the same sign, the coulomb force is positive but repulsive, while with 2 masses the gravitational force is positive but attractive
If you have two point objects both the same positive charge and both of the same mass at a distance $r$ from each other.
The force between them due to gravity is $F_g=\frac{Gmm}{r^2}$ and $F_g$ is ...
0
votes
0answers
32 views
How can I determine the magnetic nature of three sealed boxes? [closed]
For my Physics class my partner and I have to do a lab assignment where we have to determine the magnetic nature of contents of three sealed boxes. My question is how can I write this information down ...
0
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0answers
50 views
Atomic force microscopy
I have these questions about force spectroscopy which I can't answer:
What is the basic principle of single molecule force spectroscopy and what is the main difference with chemical force microscopy? ...
12
votes
1answer
370 views
Do modern Formula One cars produce enough down-force to drive upside-down?
For example, if they were driving at top speed through a long tunnel, could they transition to and stay on the ceiling?
2
votes
1answer
94 views
Swords, impacts and elasticity for a noob
So I'm a game developer and I'm trying to understand some (extremely) basic facts of impact mechanics. I had read something entitled Dynamics of Hand-Held Impact Weapons, but it was a bit too ...
0
votes
0answers
194 views
Torque required to rotate Drum [closed]
What Torque will require to rotate a Drum about horizontal axis XX.
Drum is filled with industrial Oil.
Weight of filled drum is $W=300 kg$.
Length of Drum $(L)=900mm$
and Diameter of Drum is ...
2
votes
7answers
2k views
What are the Constraints on Building a Tower to Space?
When I was a boy I used to daydream about building a tower so tall that the top of it would stick out of the top of Earth's atmosphere project into near space.
There would perhaps be a zero gravity ...
0
votes
0answers
138 views
Torque required to rotate sand mixer [closed]
the given data is-
Mixer having one impeller(rotor) rotating in horizontal plane about vertical axis.
capacity of mixer to design $C = 250kg$
rotor dia. $D = 45" = 1143mm$
friction coefficient ...
0
votes
0answers
300 views
How to find Rotational and Translational Equilibrium of Hanging Masses on a Bar?
I am making a hanging mobile which needs to be done mathematically by calculating torque. The problem is, I can't seem to figure out how to solve for the distance of the two masses from the pivot ...
2
votes
1answer
88 views
Forces: Worth worrying anything?
I am a general physics student, I had a question in my text-book and according to it two students having gravitational attraction between them = ($6.67\cdot10^-8\ \mathrm{Nm}^2/\mathrm{kg}^2$) is not ...
3
votes
3answers
971 views
Can the Lorentz force expression be derived from Maxwell's equations?
The electromagnetic force on a charge $e$ is
$$F=e(E+v\times B),$$
the Lorentz force. But, is this a separate assumption added to the full Maxwell's equations? (the result of some empirical ...
3
votes
2answers
174 views
Do we exert more force when we walk?
When we walk, is the magnitude of the earth's force on us greater than if we were standing still?
2
votes
1answer
75 views
Vertical Load Reactions On A Ramp
Hello,
I'm working on a small hardware project.
I have two load sensors located at distance $S_1$ ($x=0$) and $S_2$. Assuming we ignore the weight of the ramp ...
What is the load on $S_1$ and ...
0
votes
3answers
134 views
Doubts with levers
I'm studying for a test of static rigid body and I'm having doubts on how to solve problems involving levers with weight.
If I have, for example, a lever 10 kilograms and 3 meters long and one support ...
2
votes
5answers
319 views
How are constraint forces represented in Lagrangian mechanics?
Suppose we try to obtain the movement equation for a particle sliding on a sphere (no friction, ideal bodies...). The only forces acting on the particle are its weight and - here's my problem - a ...
0
votes
0answers
73 views
Forces and reaction forces generated by a linear actuator [closed]
A linear actuator is wedged between two solid walls as shown in the diagram below. The linear actuator is pushing outwards at its maximum rated force of 10N. What are the magnitudes of the forces ...
4
votes
2answers
135 views
Is Brian Cox right to claim that Gravity is a strong force for large masses, is it wrong, or is it only a matter of interpretation?
I watched a program of his in which it was claimed that since mass bends space in accordance to General Relativity, then in the case of very large stars it becomes a strong force to the point of being ...
0
votes
1answer
123 views
Mechanics Question: Work and Power
I'm a pure mathematician by trade, but have been teaching myself classical mechanics. I've got to the chapter on Work, Energy and Power and I've found an example that is causing me some problems.
...
2
votes
3answers
307 views
The two faces of $F = m*a$
As I have understood,
$F(t)=m \cdot a(t)$
can have 2 different meanings:
When applying an external force $F$ on a point mass of mass $m$, the resulting acceleration of that mass at time $t$ is ...
2
votes
2answers
773 views
What happens to a fly floating in the air when the train starts moving
I was wondering, within a static train, for a fly which is currently floating in the air and not moving at all, what will happen if:
The train starts to accelerate and move forward. Will the ...
3
votes
1answer
62 views
Will a gas keep forever in a “perfect” flask?
I've been wondering about the porosity of materials, I know that, for example the air comes out of tires/balloons because (besides having huge gaps on the rim contact area/knot) they are made of a ...
5
votes
1answer
357 views
Do all the forces become one?
Were the forces of nature combined in one unifying force at the time of the Big Bang?
By which symmetry is this unification governed?
Are there any evidence for such unification of forces?
Has ever ...
6
votes
3answers
230 views
Tidal force on far side
I have a question about tidal forces on the far side of a body experiencing gravitational attraction from another body.
Let's assume we have two spherical bodies $A$ and $B$ whose centers are $D$ ...
5
votes
0answers
26 views
Measurement of Tangential Momentum Accomodation? [duplicate]
Possible Duplicate:
Measurement of Tangential Momentum Accomodation?
I am using atomic force microscopy (AFM) for characterizing
pores of the size of nanometers for application in gas ...
1
vote
0answers
474 views
Newton's second-law word problems with coefficient friction [closed]
Here is an example problem:
A sled of mass 50kg is pulled along a snow-covered, flat ground. The static coefficient of friction is 0.30, and the kinetic coefficient friction is 0.100. What force ...
6
votes
2answers
9k 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 ...
1
vote
0answers
79 views
What is the angle of the string with the vertical?
A heavy uniform sphere of radius $a$ has a light inextensible string
attached to a point on its surface. The other end of the string is
fixed to a point on a rough vertical wall. The sphere ...
0
votes
0answers
121 views
How to find the average force opposing motion down a slope? [closed]
A skier of mass 75 kg accelerates from rest down the slope as shown in the diagram. At the bottom of the slope, he is traveling at 40 m/s.
What is the average force opposing his motion down the slope? ...
3
votes
4answers
741 views
Is it possible to lift yourself off from the ground?
Say for instance a person who was strong enough to lift double his body weight. If he placed his hands under his bottom and tried to lift$^1$ himself$^2$ off the ground, could he?
--
$^1$In a ...
0
votes
4answers
731 views
Would you feel weightless if falling or flying up in a vacuum?
Ignoring that you can't survive in a vacuum.
If you were to jump of a ledge in a vacuum (in a vertical tube eg). While falling would you feel weightless? Surely the earths gravity is still pulling ...
7
votes
3answers
308 views
Force through quantum mechanics
In classical physics force is:
$$F=\frac {dp}{dt}$$
How about quantum mechanics?
In Old Quantum Mechanics momentum is: $p=\hbar \cdot k$ so force will be:
$$F=\hbar \frac {dk}{dt}$$
what does $\frac ...
4
votes
1answer
173 views
Can i use coils with compressed air to make a superconductor?
What im saying is inside pipes i am going to use compressing so that that in the places with low pressure they cool the superconducotor. is this possible? Can i use this concept to make ...
1
vote
1answer
69 views
Why doesn't pushing balls in a tube propagate the movement faster than the SoL? [duplicate]
Possible Duplicate:
Is it possible for information to be transmitted faster than light by using a rigid pole?
On one episode of QI they asked the question, "How fast do electrons move ...
0
votes
1answer
76 views
Finding the acceleration of Block attached using tricky string setup
Below shown is a setup, and block B starts from rest and moves towards right with a constant acceleration. Does the acceleration differ for the blocks ? I am a bit confused because of the tricky ...
4
votes
1answer
180 views
How are forces related to decays?
How are decays related to forces, what is meant by particle X decays through the, say, strong force?
The way I understand forces is by how they change the acceleration of particles with the right ...
3
votes
6answers
600 views
Do you feel gravity?
I have been reading a few articles about the question why we don't feel/notice gravity in everyday life, but I couldn't understand why exactly we don't feel/notice it, that is, why we don't feel a ...
7
votes
4answers
455 views
Which direction will the yoyo move?
This question has been around the net for a while, and I haven't seen a good explanation for it:
A yo-yo is initially at rest on a horizontal surface. A string is pulled in the direction shown in ...
0
votes
1answer
82 views
Nothing escapes BHs, gravitons mediate gravity, so why do BHs gravitate? [duplicate]
Possible Duplicate:
How does gravity escape a black hole?
Nothing escapes black holes, gravitons mediate gravity, so why do black holes gravitate?
My question is, "where is the hole (no ...
0
votes
2answers
194 views
What is the force of friction between two bodies given their masses and a force pulling them as a unit accross a surface?
Where a force of 200N pulls two blocks together(as one system) across a horizontal table top(µ=0.800)
$m_A$ = 5.00kg, $m_B$ = 10.0kg
Find the acceleration of the system.
Find f$_k$ between B and A
...
7
votes
5answers
272 views
Why don't we use the concept of force in quantum mechanics?
I'm a quarter of the way towards finishing a basic quantum mechanics course, and I see no mention of force, after having done the 1-D Schrodinger equation for a free particle, particle in an ...
1
vote
1answer
61 views
How to express answers where inequalities are involved?
Part of the floor of a workshop is inclined at 10 degrees to the horizontal. This is to allow the safe storage of steel cylinders. A cylinder of mass 7000 kg is stored as shown in the diagram (c the ...
1
vote
1answer
256 views
Kinetic Energy And Rotational Motion
The problem is, "A metal can containing condensed mushroom soup has mass 220 g, height 11.0 cm and diameter 6.38 cm. It is placed at rest on its side at the top of a 3.00-m-long incline that is at ...
0
votes
2answers
764 views
Confused on how to properly use right hand rule
I am having trouble using the right hand rule properly and often find myself putting my hand in awkward orientations. I know you point your hand in the direction of $r$ and then point your fingers in ...
0
votes
1answer
478 views
Mass-Spring Damper system - moving surface
I need help with a physics problem, I don't know much about dampers, how can this be solved?
we have
$y_0(x)=\mu\sin(\Omega x)$
We arrive at this equation for motion (where we define $b$ and ...
0
votes
2answers
2k views
Tensions And Pulleys With Masses
The problem I am working on is:
"A block of mass m1 = 1.80 kg and a block of mass m2 = 6.30 kg are connected by a massless string over a pulley in the shape of a solid disk having radius R = 0.250 m ...
2
votes
5answers
267 views
Is there a mathematical derivation of potential energy that is *not* rooted in the conservation of energy?
For simplicity I'll consider only gravity, but in general this question only applies to conservative forces.
As per my understanding, the way one gets to the equation for gravitational potential ...
7
votes
4answers
774 views
Is the EmDrive, or “Relativity Drive” possible?
In 2006, New Scientist magazine published an article titled Relativity drive: The end of wings and wheels1 [1] about the EmDrive [Wikipedia] which stirred up a fair degree of controversy and some ...
4
votes
2answers
655 views
Calculate stainless steel pole necking limit
Background
Trying to determine how much weight a post can support without necking when a monitor is attached to an articulated arm: a cantilever problem.
Problem
There are three objects involved in ...
