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 ...

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1answer
112 views

Are all conservative forces a central force?

If a force is a central force and can be written as $\vec{F}(\vec{r})=f{(r)}\hat{r}$ , then it is a conservative force. But is the converse true? I mean, are all conservative forces a central force? ...
0
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0answers
61 views

Cavendish Experiment [on hold]

Would the earth’s gravity overpower the gravity of the much smaller and less dense lead spheres?
2
votes
2answers
163 views

Balancing forces on a liquid [closed]

My reasoning is as follows Atmospheric pressure = $P_{0}$; Spring stretch = $x$; Pressure under top piston = $P$ Balancing forces on top piston $kx + P S_1 = P_0 S_1$ Balancing forces on bottom ...
29
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7answers
5k views

Supergun Launching of Satellites

I should say first that I don't believe this is a feasible launch method, otherwise NASA and other space agencies would be using it by now. It's based on this BBC news story Saddam Hussein's Supergun ...
10
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3answers
2k views

Physics behind the “Switch Pitch”?

I've come across this toy called a "Switch Pitch" designed by Chuck Hoberman. It's a ball that when tossed into the air (with some amount of rotation), inverts and changes colour. Made of plastic, ...
3
votes
2answers
48 views

Force against mg when block is connected to block and held horizontally

In the image attached, what would be the force that would balance out the gravitational force $mg$? The block is also not accelerating downwards so there should be some force acting on the block to ...
5
votes
4answers
126 views

Rotating the bucket in circular motion without spilling water

In the bucket experiment when the bucket reaches the top of the circle why will it have a normal force acting on the water downwards? Doesn't normal force oppose any other force? There is no force ...
0
votes
1answer
237 views

Inclined plane, circular motion and the friction

Suppose we have a cylinder on an inclined plane of mass $m$ and radius $R$ moving without sliding (so that $\varepsilon = a/R$). Why is the friction $F$ causing the circular motion sometimes lower ...
-1
votes
1answer
19 views

External and internal resistance to airflow

If an aircraft was travelling at 100mph an hole was opened to allow 100mph into the cabin,then the airflow is feed into an amplifier like a ramjet and the airflow out of the ramjet was increased to ...
6
votes
5answers
9k views

If a space ship accelerated constantly, would its astronauts constantly feel the forward movement?

I know that if a space ship suddenly traveled very fast, its astronauts would be fly against the back wall, potentially getting hurt. If the space ship suddenly stopped, they would also fly against ...
2
votes
3answers
45 views

Force at axis of spinning wheel

This is a newbie question, but I don't quite understand the forces at work when an object is rotating. So I've read that i can use my right hand to determine the direction of the force at the axis ...
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0answers
16 views

what is the reaction force of electromagnetic force created on a conductor in a magnetic field? [on hold]

If a force is created on a conductor carrying a current in a magnetic field, what does the reaction of this force act on?
1
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1answer
207 views

Can two bodies of different mass attached at ends of string passed over a frictionless pulley produce equal tension on both sides?

In my textbook there is given a case that to calculate acceleration and tension produced in string when string is attached at it's ends with two bodies of masses such that $m1>m2$ and the tension ...
1
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2answers
62 views

Model/formula for bouncing ball

I'm programming an animation of a bouncing ball, and I want it to be as realistic as possible. I fully understand the physics while the ball is rising and falling: It accelerates downward at 9.8 ...
3
votes
2answers
1k views

Average Force vs Net Force

The F in $$Impulse = F*t$$ is said to be the average force. For a ball dropped vertically onto a horizontal surface, the average force, F, on the ball from the floor is: $$F = \frac{\Delta{p}}{t}$$ ...
0
votes
1answer
136 views

Can two bodies move with equal acceleration if forces acting on both are unequal?

In my textbook there is a case given that is to find acceleration and tension produced in a string passed over a frictionless pulley and attached with bodies of different masses at its ends. Now below ...
0
votes
1answer
45 views

Double Integrals of Force

I took AP Physics C and Multivariable Calculus last year, and noticed something interesting. For non-relativistic particles in one dimension:$$F=\frac{\partial p}{\partial t}=\frac{\partial ...
-1
votes
1answer
28 views

Calculate the average force exerted by the bat on the ball [on hold]

A cricket ball of mass 150 g is moving with a velocity of 12 m/s and is hit by a bat so that the ball is turned back by a velocity of 20 m/s. The force of blow acts for 0.01 second on the ball. ...
1
vote
1answer
40 views

What kind of damping is this $F = -ax|x'|$?

From Applied Mathematics by Logan: A mass hanging on a spring is <...> governed by $$mx'' = -ax|x'| - kx$$ where $-ax|x'|$ is a nonlinear damping force. I looked up "nonlinear damping" ...
3
votes
1answer
58 views

Height formula of a sphere inside a pipe

I have a pipe with a ball inside it and a blowing air through it. Look this image: The air is blowing in the direction of $F_a$. $F_a$ Is the air force and $P$ is the weight force. What I want ...
0
votes
0answers
26 views

Calculate force required to lift an object to a certain height in a required time [on hold]

This is my first question in stack physics so not sure if I'm phrasing this right. I'm a 9th grade student and this is not a school project. My idea actually. Anyways Say I have a object of weight ...
0
votes
2answers
39 views

Balancing Orthogonal Forces on 2D plane with arbitrary placement [on hold]

I have a rectangular block in the xy plane with the center of mass that acts in the z direction at an arbitrary place in the plane. I also have 4 legs that support this weight underneath the block. ...
0
votes
2answers
247 views

We cannot solve this inclined plane problem, right? [on hold]

We drag a sledge along a snow-covered hillside with constant speed. Distance is 150m. The time it takes to reach the top is 300 secs. The sledge is 12kg. And the coefficient of friction $\mu$ = 0.04. ...
0
votes
1answer
42 views

Why does a bungee jumper continue to move downwards beyond the equilibrium position of the jumper and cord?

When a bungee jumper jumps, ignoring the mass of the bungee cord, the jumper initially falls in freefall before an inelastic collision occurs between the jumper and cord, and the cord extends as the ...
0
votes
1answer
28 views

Energy Transferred to a Spring by a Time Dependent Force (using Fourier Transformations)

I found an excersice in Byron-Fuller's: "Mathematics of Classical and Quantum Physics", about the energy which is transferred to a spring by a time depended force of the form: $F(t)=\left\{ ...
3
votes
1answer
42 views

Force and Torque

Think of a uniform sphere. Sometimes if a force is applied to the sphere it does not only move but also spins. So there is a torque. But is it possible to calculate which part of the applied force is ...
1
vote
1answer
56 views

Raising a cut on your arm above your heart

I often read that when you have a deep cut on your arm, you should raise your arm to the point where the cut is above your heart. This should reduce the amount of blood loss because less blood reaches ...
1
vote
2answers
13 views

Difference in Energy Transfer Between Impacts and Nudges [on hold]

Say I have a table and I want to produce a vibration in the table. Would I be better off impacting the surface of the table (i.e. smacking the table) or nudging the surface (i.e. leaning on the ...
1
vote
0answers
47 views

Does a ball bearing cause bigger tides than the moon?

As per the answer to this question it is suggested the relative tidal pull of objects of equal angular area is equal to their relative density. Which lead me to the click-baity question: Does a ball ...
3
votes
1answer
149 views

induction of van der Waals forces

Is there a way to maximize van der Waals forces between two materials, by electrifying one material, thus creating dipoles/instantaneous dipoles and thus creating stronger van der Waals forces? has ...
-1
votes
0answers
26 views

How one fly using allomancy? [closed]

Actually this question is related to the allomancy of Mistborn series. Suppose if there is body that can steel push. Then initial weight is balanced by normal reaction. froce due to steel push is ...
1
vote
2answers
370 views

Ball flying towards me - Newton's third law is violated?

I was trying to answer the question of the flying ball here on the basis of Newton's third law and momentum conservation. Here is what I have tried. Lets take a ball mass of $m_1$ (index 1 is the ...
0
votes
0answers
25 views

Could this garage door's bowing be caused by someone falling into it? [closed]

The tension spring broke on our garage door causing it to fall. Afterward, the garage looked as it does in the pictures below. The most straightforward explanation to me is that the impact of the fall ...
0
votes
4answers
261 views

Forces Create Angular Acceleration And “Straight” Acceleration - But How Much Of Each?

Let me set up the following problem for a rectangle floating in space: We know its dimensions. We know its mass. There's a force pushing it for a known amount of time - we know the angle & ...
0
votes
0answers
19 views

Vertical Scale Acceleration Values [closed]

The following is an acceleration-versus-force graph for a 500 g object. What acceleration values go in the blanks (a and b) on the vertical scale? I just need a little bit of coaching as to whether ...
0
votes
1answer
118 views

Magnetic interaction of wire and rectangular loop

In this video, Prof. Lewin shows an infinitely long wire and a rectangular loop at a distance $r_1$ from each other, each carrying a current. He then calculates the magnetic field resulting from the ...
0
votes
0answers
68 views

In the figure shown, what is the magnitude of the acceleration of the vertically suspended block as it falls? [closed]

I started by drawing out the free body diagrams of both M and 2M and got: for block M i got the equation (looking at the diagram): $F_{down}=ma_{down}$ $T-Mgsinθ=Ma$ (D'Alambert's principle) ...
4
votes
5answers
599 views

What is the significance of Planck force?

I have been curious to find what could be the significance of Planck force? It is calculated by the formula $c^4/G = 1.21031359\times 10^{44} \, \mathrm{N}$, where $c$ is the speed of light and $G$ is ...
6
votes
1answer
437 views

Derivation of force law in special relativity

I've seen force defined in special relativity as the rate of change of 4-momentum $$ {\bf{F}} = \frac{d {\bf{p}}}{dt} $$ Can anyone comment on the following derivation of that relation? Take one ...
7
votes
5answers
133 views

Astronauts on a tether

Recently, I went to a competition with a science test. One of the questions was as follows: Two astronauts (A and B) are tethered together in space. Simultaneously, Astronaut A pulls on the tether ...
3
votes
0answers
48 views

Why is diproton unstable? [duplicate]

Diproton is an isotope of helium without any neutrons. It commonly forms in the Sun, where protons are fused constantly. However, it is extremely unstable, and will revert back to two protons almost ...
-1
votes
0answers
26 views

What is the horizontal acceleration of the block? [closed]

A 2.0-kg block slides on a horizontal surface. A force (P = 6.0 N) is coming at the block as a 30° angle pushing on the block to the right. What is the horizontal acceleration of the block? So ...
0
votes
2answers
115 views

Few questions related to Tension

I am struggling with the concept of tension in a rope. Below specific questions. I am understanding tension to be an elastic force between rope molecules. If so, is it fair to say the net tension ...
0
votes
1answer
281 views

Question on Binet's equation

Is there a difference in Binet's equation when the force acting on a body is attractive and repulsive? I mean, if the force has a magnitude $F(r)$, is it Binet's equation always ...
4
votes
3answers
1k views

Has a body angular momentum and torque only in a circular path?

In different contexts, my book(Principles of Physics by Resnick, Halliday ,Walker) , they wrote For torque, the path need no longer be a circle and we must write the torque as a vector ...
2
votes
1answer
38 views

What amount of force could be created by a person “swimming” in air?

Had a question on a physics test, a person is at rest on a frictionless surface and can not throw anything, can they move? I said yes, by "swimming" against the air and got docked because "it ...
1
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3answers
38 views

How is rotational torque calculated when a force is applied uniformly over a surface?

Currently, the formula I am using to calculate the rotational torque applied onto an axis is $T = Fr\sin \theta$, where $T$ is the torque (in $\mathrm{N\ m}$), $F$ is the force acting, $r$ is the ...
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votes
0answers
20 views

solving force vector calculation [closed]

$AC= 1\ \mathrm{cm}\land3.8\ \mathrm{N}$ $AB= 17.5\ \mathrm{cm}$ Corner $ABD= \alpha$ Question: How many newtons is force vector $AB$? My solution so far is not even near the solution on the ...
1
vote
3answers
255 views

Centripetal and centrifugal force

If a stone is rotated with the help of a rope, then both centripetal force and centrifugal force will be liberated. The magnitude of that forces are same, but direction of them are opposite to each ...
0
votes
1answer
25 views

How does string tension influence the harmonic spectrum?

Hey there fellow physicists & musicians! I have a question both physics and music related. How does the string tension affect the sound spectrum? More precisely, how do the respective ...