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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1
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1answer
684 views

How is the fall time for a parachute affected by the mass of the load?

Why do parachutes with a heavier load fall faster than a parachute with a lighter load?
2
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1answer
51 views

Reaction force explanation? [closed]

I heard that reaction force is the total force applied back due to electromagnetic repulsion between the atoms of the thing that exerted the force and the thing that the force was exerted on, so can ...
0
votes
2answers
110 views

Gravitational force acting on two particles

According to Newton's Laws of Gravitation, $F=Gm_1 m_2/r^2$ So gravitational force F is directly proportional to $1/r^2$. Now if we consider 2 point masses in vacuum at rest at a distance 'd' apart,...
2
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1answer
64 views

Does Hooke's Law apply for microscopic amounts of compression?

I would like to set up a simple laser interferometer to measure the compression of a material experiencing forces around $8 \times 10^{-4}$ N. But I need to find the spring constant to calculate the ...
8
votes
4answers
432 views

Is work done by a pseudo force?

If a body is viewed from the frame of another body which is itself accelerating, will work be done by the pseudo force acting on the first body in the frame of second body ( provided the first body is ...
0
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1answer
60 views

Formula connecting Force and Power

Is there such formula? There probably is of course, but i would like a very concise description of how to derive it, in order to better understand myself. Thank you in advance.
0
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0answers
35 views

Diamagnetic Sphere Moving through Solenoid

I've seen the videos of frogs being levitated due to diamagnetism. What happens if the frog (or another diamagnetic object) enters a solenoid with an initial velocity? Specifically, consider a ...
0
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2answers
89 views

Does the frame of reference change the behavior of a particle

"Behavior" word in the title is not very correct. I'm in a train at a railway station and on the platform there is a glass case (the mass of case is 5 kg and if it gets hit with a velocity of 10 N ...
0
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1answer
199 views

Calculating output forces of bicycle wheels

Based on the force on the rear gear $F_t$ and the radii of the rear gear $R_g$ and rear wheel $R_w$ , how would you calculate the force the bicycle exerts on the ground when it is accelerating? I ...
0
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1answer
199 views

Calculate Spring Constant [closed]

I am editing the question because it was misunderstood to be a homeowrk question. I am modeling a Stumps equipment for a game called Cricket.Typically the game consists of 3 wooden stumps ...
1
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2answers
211 views

Why does the superposition principle work in method of images?

Okay, let there be a conducting sphere having radius $a$ initially charged with $Q$ & insulated. Now, $q$ is brought in front of the conductor at $y$ from the center. Now, Jackson in his book ...
0
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2answers
512 views

Horizontal and vertical acceleration of a ball on a slope?

I understand that you resolve the components of the balls weight parallel and perpendicular to the slope in order to calculate the force due to gravity that actually acts down the slope. The ...
0
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2answers
56 views

Pertaining to Newton's laws, how do so many objects acheive perfect equilibrium?

Suppose a light is hanging from a ceiling. Supposedly, the force of tension pulling it up is exactly the same as the force of gravity pulling it down. Why is it that the tension happens to be exactly ...
1
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2answers
96 views

Why does the ground always push up?

In the example of a bouncy ball being thrown at the ground, at some angle from the normal, $\theta$, we know that the ground will apply a force in the normal direction, causing the ball to rebound at $...
0
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0answers
57 views

Is it wrong to equate the net force to the force by the spring to find its maximum expansion?

In the picture displayed here , I have two blocks of masses m1 and m2. They are connected by a spring and a leftward force is applied on the block of mass m1.This will , ofcourse , result in expansion ...
0
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1answer
142 views

Why is it effectively impossible to balance this rectangle block on a triangle block? (See photo)

I've always wondered why it's basically impossible to balance a rectangle block on top of a triangle one like this. This is my nine-year-old giving it a try. I have never in my life gotten it to ...
0
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2answers
96 views

How does friction act on a body, if only 2 regions on it are rough? [closed]

While tackling an Olympiad question, it came to my mind that friction need not act in the same direction at all points on a body. I thought of using integration to evaluate the net frictional force, ...
1
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2answers
111 views

Why is sometimes more difficult to lift a baby?

I have a small cousin and she enjoys when I pick her up, which I can do pretty easily. Sometimes though she decides she wants to make my life difficult, and when she decides so, she tells me she is "...
0
votes
4answers
545 views

Why Do Objects move?

Let's imagine a block resting on horizontal table. When We apply a force which is greater than frictional force it moves. But why does this happen? Why can't friction withstand any force? As we know ...
1
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1answer
55 views

Extension spring and permanent damage

Is there a way to calculate how far an extension spring can be extended before it suffers permanent damage? There are some online calculators, but how are they done? This calculator is the most ...
0
votes
1answer
158 views

Moments and forces, when part of the scenario involves a circle or arc rather than a straight line

Some questions below, involving strategies, regarding the following problem: A hoop of weight $20$ Newtons can rotate freely about a pin fixed in a wall. A string has one end attached to a pin, ...
2
votes
1answer
36 views

Could an internally tethered rocket cause external movement?

Imagine a scenario where a large box is floating freely in space. There is a vacuum both inside and outside of this box. Also imagine that a dormant rocket is inside this box, but it is loosely ...
3
votes
4answers
351 views

Is there difference in force when the height increases?

Consider a man with mass 50kg. When he jumps from a 2 meter height, the total force is $F=ma$ ie (mass * gravity), but nothing happens to him. When he jumps from a 50 meter height, the total force ...
1
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2answers
590 views

How to draw a formal free body diagram for a object at rest on a inclined plane?

Five choices I made up: a. b. c. d. e. One thing I know immediately is that the vectors have to cancel each other at last so there is no net force acting on it. a. certainly qualifies....
0
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2answers
327 views

Vertical circular motion: minimum velocity

In vertical circular motion while finding the minimum velocity at the bottom-most point for looping the loop, why do we take the tension at the topmost point to be zero?
0
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3answers
576 views

Rate of Acceleration of an Object Pulled by Magnetic Force

Gravity on earth pulls objects toward it with an acceleration of 9.8 m/s/s on Earth until the object reaches it's max potential free fall speed. (I call this terminal velocity though I think that this ...
0
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2answers
160 views

Does a body always rotate purely about its center of mass? [duplicate]

For example : A rod is held stationary in vertical position on a smooth horizontal ground and then released. Now the center of mass has velocity and acceleration and every point of the rod has some ...
2
votes
5answers
183 views

No need Power to fly ? Paradox [duplicate]

I would like to know how much power I need for magnetic levitation. $$P = Fv.$$ $F = F_g \approx \text{mass} \times 10$, okay. But $v = 0$! I can't believe I need no power to keep an object in the ...
0
votes
1answer
73 views

Rocket thrust over time [closed]

I have calculated the thrust of a rocket, and it's burn time for an orbital manoeuvre. I need to know how much force is applied on the rocket every half-second. How would I go about doing this? ...
0
votes
2answers
73 views

What objects' masses do we need to take into account when calculating force?

In the following problem: A steam engine of mass $3\times 10^4\ \mathrm{kg}$ pulls two wagons each of mass $2\times 10^4\ \mathrm{kg}$ with an acceleration of $0.2\ \mathrm{m/s^2}$. Neglecting ...
1
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4answers
278 views

How far apart do two objects have to be for there to be negligible force between them?

Inspired from the commentary on this question. How far apart do two objects have to be for the gravitational force between them to be negligible? By negligible I mean, that it could never be ...
73
votes
6answers
15k views

Am I attracting Pluto?

My question is simple: as the title says, am I exerting a force over for example Pluto, although it is a very small force, it is there, right? Or maybe let's go further: Am I exerting a gravity force ...
0
votes
1answer
65 views

Unification: what does it mean for the forces to become equal?

The Coulomb force constant $k_c$ has si-units of $Nm^2C^{-2}$. The gravitational force constant $G$ has si-units of $Nm^2kg^{-2}$. What does it mean that at very high energies these forces become ...
0
votes
1answer
174 views

Is there surface tension between a solid and a liquid?

The molecules of a solid are so tightly bound together that they are fixed in position unlike in a liquid or gas where they may move freely. In that case it seems like the surface tension between the ...
5
votes
2answers
149 views

What is it exactly that conflicts when trying to unify all 4 fundamental forces?

Everyone knows that there are 4 fundamental forces: Gravity Electromagnetic Weak Strong At school and university you're taught that no one has been able to unify these 4 fources. However, not a ...
1
vote
1answer
64 views

Why does the axle need to be rotated in a turbine generator?

Inside a turbine a wire rotates between the poles of a magnet, i.e. rotating inside the magnetic field, so that the field forces the electrons in the wire to move and generate current. But why does ...
0
votes
1answer
79 views

Question about solving Newton's laws' problems [closed]

A questions from my textbook asks me what the force by the pulley on the roof is. In order to answer the question, need I consider those objects hanging from both sides of the rope, or need I only ...
-3
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2answers
69 views

Factors that affect the speed of body? [closed]

I want to know that what are scientific factors that restrict cars to overcome 450km/hr?
0
votes
2answers
150 views

What should the brake force in this problem be? [closed]

Alright so I think I know how to do this but I require help in calculating what acceleration would be in terms of some sort of friction coefficient. So model a particle going down a hill. The slope ...
0
votes
5answers
4k views

Pulley system: how can tensions be equal throughout a entire rope if the weights on opposite ends are different? [duplicate]

More weight means more pulling force, and thus more tension force. Like this answer says, however much force you pulling with is equal in magnitude to the tension force. If that is case, how then ...
0
votes
1answer
60 views

An Electron Chasing Another

An electron is held in place in deep space. Another electron approaches with speed $v_0$. When the approaching electron is a distance $r_0$ away from the first electron, the first is set free. The ...
0
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0answers
51 views

Need help piecing together football trajectory equations

I've done some studying of the physics involved when estimating the trajectory of an arcing football; that is, in American football, not world futbal, per se. I have all the basic building blocks I ...
0
votes
2answers
95 views

Simulation of a simple robot [closed]

I'm a programmer and I'm working on a simple robot simulator. Of course, the most important part of this simulator, is the physical simulation of the robot. Unfortunately, I have a little knowledge ...
0
votes
0answers
100 views

Calculating atomic forces from total force and torque on molecule in molecular dynamics (MD)

I guess this problem applies to any body that is composed of a small number of particles, but for the sake of simplicity and concreteness, let's consider a classical model of a molecule consisting of ...
1
vote
1answer
103 views

Magnetic force paradox

Suppose a current carrying wire Is placed in vertical direction. A charged rod is placed is placed nearly horizontally.It is clear that magnetic field due to current carrying wire is inside the paper....
0
votes
3answers
2k views

How do suction cups work?

My roommate and I are having trouble agreeing on how suction cups work. Presumably, the ambient air pressure is the only thing which keeps the suction cup attached to the object. When lifting an ...
5
votes
4answers
156 views

Why is it easier for the ocean to push someone over by exerting force on their front side than by exerting force on their left or right side?

If I put two clones of normal weight on a beach in the ocean, with one standing perpendicular to the waves, and the other standing parallel to them, the one standing perpendicular to the waves will be ...
3
votes
2answers
793 views

Acceleration of a ramp

If we have a ramp and a block on it, and if all the surfaces are frictionless so both the the ramp and block can move. Is the normal force different from the time that ramp is not moving? If yes can ...
-2
votes
1answer
155 views

Tension in the string produced due to pulling vs pushing

I know that tension is produced when we pull the rope, but what if we push it? What would that be called? Is that tension too? Negative tension?
2
votes
2answers
266 views

Which moment of intertia do I need to calculate torque

I'm trying to calculate the torque needed to rotate an array of solar panels. I've found some formulas for calculating torque, but they require moment of inertia. I designed this array in Autodesk ...