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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3answers
33 views

Reaction force?

When I push a pure cube of iron (full of iron and has no space in it) where is the reaction force?. Like when I exert a force on a car to move it forward there will be a reaction force backward on ...
1
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0answers
22 views

Calculating the force applied by an electromagnet on a ferromagnetic object

I know how to calculate the force applied on a magnetic object by an electromagnet at $n$ metres distance using $$F = \frac{(N \cdot I)^2 \cdot k \cdot A} {2 \cdot g^2},$$ but how would one calculate ...
0
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1answer
47 views

Calculate Spring Constant

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 ...
-3
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0answers
16 views

Controlling the flow of powder from a container, based on grams selected [on hold]

was wondering how you would control the flow of powder from a container (with a small cylindrical dispenser at the bottom). The container is filled with powder. As the container drains, less ...
1
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2answers
87 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 ...
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2answers
36 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
87 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 ...
-1
votes
0answers
24 views

How much do the rear and front, side-parts of this 2,400 lb. car weigh? [on hold]

The car is to be lifted from the body right above the tire, which is around 1 inch or so outward. Since the car is even it should weigh almost exactly (to the nanogram) the same on the back and ...
0
votes
2answers
51 views

Ball throwing problem [on hold]

A ball of mass 0.2 kg is thrown vertically upwards by applying a constant force by hand.if the hand moves 0.2 m while applying the force and the ball goes upto 2 m height further, find the magnitude ...
0
votes
1answer
53 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 ...
-2
votes
0answers
45 views

Work done by a constant force

Is a constant force always conservative? What I tried (Assuming $F$ and $dr$ to be in same direction ) $W=\int Fdr$ Now since $F$ is constant hence it becomes $F \int dr=F \times ...
0
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2answers
46 views

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

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
vote
2answers
72 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
121 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
vote
1answer
22 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
2answers
31 views

About angular movement of pendulum [closed]

I have designed a pendulum of weight $1.46\text{g}$. I need to know what angle the pendulum may take at a linear acceleration of $200~\text{ m/s^2}$. Below I attached the image of pendulum. Please let ...
0
votes
1answer
45 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
35 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
73 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
vote
2answers
48 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 ...
0
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2answers
45 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
votes
0answers
25 views

Formulas for Calculation of Segway style scooter? [closed]

I know this may have been asked a lot, but by going from many sources of figuring out the specs of motor and battery, I was getting answers as varied from 7.5W to 150W! Thought I should I ask ...
0
votes
3answers
57 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
votes
0answers
10 views

can I move electromagnetic items in a plane at any direction? [closed]

Lets say we have some balls or other shapes that can be electromagnets (with the relevant electrified coils etc). I want to place stationary electromagnets at the edges of their plane and generate a ...
1
vote
0answers
29 views

Forces acting in a system of a bar suspended by two rods [closed]

So, say I have a bar with a mass of $350 kg$ and it is being suspended by two beams (AC and BD). All joints; A, B, C & D are hinged. At a particular instance, a horizontal force of $1500 Newtons$ ...
0
votes
2answers
83 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 ...
0
votes
1answer
33 views

Movement of a super ball after it hits the wall! [closed]

First look at this image and then I will explain the question! We have a highly elastic ball like a super ball and we throw it into the space between to plates . After some encounter and under some ...
2
votes
5answers
142 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
36 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
47 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
vote
4answers
159 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 ...
0
votes
1answer
38 views

Friction between two bodies placed one above another [on hold]

I'm recently facing a bit confusion regarding the friction between two bodies. Suppose there's two bodies, one placed on another. There is frictional force $ f $ between the base body and floor and ...
70
votes
6answers
14k 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
44 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
51 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
104 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
25 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
36 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
votes
2answers
31 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
48 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
95 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
53 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
votes
0answers
15 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
53 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
20 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
81 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 ...
0
votes
2answers
45 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 ...
0
votes
1answer
25 views

Why is it easier 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
75 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
34 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?