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
71 views

Understanding the relationship between electric energy and force

I'm trying to do the following problem: One of the three types of radioactive decay is "β decay", during which protons decay into neutrons or vice­versa, emitting either electrons (β­) or positrons ...
1
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5answers
179 views

Why am I not accelerated by the reaction force applied by Earth on me? [duplicate]

Newton's third law says that "to every action, there is always an equal but opposite reaction". And Newton's second law of motion says that, $F=ma$ $=>$ $a=\frac{F}{m}$. People says that If I stand ...
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1answer
16 views

Why friction is not taken to be varying jointly as roughness of the object along with normal force?

Frictional resistance to the relative motion of two solid objects is usually proportional to the force which presses the surfaces together as well as the roughness of the surfaces. But when we talk ...
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2answers
55 views

How does the earth do a negative work on a static body? [closed]

If a body is in rest and the earth acts with a force on it 10 N Is there a negative work done by the earth though the body doesn't move? how? does it have a common thing with potential energy?
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1answer
26 views

If two bodies move opposite to each other when brought in contact, what is the direction of force of friction?

We know that when a body is at rest and other is dragged over it then a force is produced which opposes the motion and consequently its direction is negative to the force applied on body to produce ...
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2answers
38 views

If the force of friction is 20 N for a moving body does acceleration increase with the increase of the mass?

A body is moving and the only force acting on it is the force of friction. If we put another body on this moving body somehow the force of friction will increase; does its acceleration change?
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3answers
228 views

Why is it easier to go uphill on a lower gear?

In cars as well as bicycles, when we are on a lower gear, the driving wheel (the one on the wheels) has a bigger radius compared to when on a higher gear. So on a lower gear the bike/car would move ...
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2answers
60 views

Calculation of a normal force with an angle

I'm currently studying forces in physics and in this example, it states that Fn +Fay = mg. Why is this so? Is it because they are both in the same direction?
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1answer
83 views

Moment of Inertia: uniform rigid rod on smooth plane [closed]

Consider a rod of length $b$ and mass $m$ on a smooth horizontal plane. A force is applied to one end of the rod. What is the acceleration $a$ and angular acceleration $\alpha$ of the other end of ...
2
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1answer
43 views

Computing the gravitational force on a planet in a particular system [closed]

I have a system of four planets moving in a 2D plane. I'm trying to write some code (C++) to find the positions of these planets at time t=3. I'm probably going to attempt this via a leapfrog ...
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1answer
47 views

What is a self adjusting force?

What is a self adjusting force? I searched it everywhere on internet but not got my answer and I have no other source to get its answer except this site so please help me.
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0answers
69 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 ...
2
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0answers
48 views

Forces acting on a ball when its squeezed [closed]

I am new to this forum. I am currently working on a project in the field of tangible user interface. I am developing a game in which a pressure sensor squeezable ball is the input controller. I am ...
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2answers
183 views

Can we define tension in a string as the reactive force produced in a string being pulled at both ends?

In my textbook, the definition of tension was given that Tension is the reactive force which exists when string is being stretched at its both end. After it there was a case given that to calculate ...
2
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2answers
258 views

Why are heavy things harder to lift?

According to multiple websites, any object in free-fall (no air resistance) on earth will accelerate towards the Earth at 9.8 m/s. If all objects fall towards the Earth at the same rate, regardless of ...
1
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1answer
54 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 ...
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2answers
32 views

Force on border exerted by a liquid

Why is it nearly universally understood that force in a liquid against a border is dependent on internal pressure, depth only, rather than weight of the liquid? Thus, for example, that the force from ...
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3answers
89 views

Object falls and hits ground - which forces are involved to change its momentum?

When an object falls and hits the ground - which forces are involved to change its momentum? Should $m\vec{g}$ be taken into account of the forces that were involved in the change of momentum?
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2answers
133 views

Is the center of mass of an object just a convention?

I am currently studying moments. The concepts are fairly obvious, but there is one thing I don't understand: the concept of center of mass. Why do we consider that the weight of a uniform object is ...
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1answer
30 views

Force of tension on both sides of one string- 2 questions

Here's something I want to ask you guys about: Many times downward N1 and N2 are ignored in exercises. Why? If forces of tension are balanced by each other, why won't objects just fall? Cheers ...
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4answers
63 views

Using formula for work with distance of 0m [duplicate]

Consider this: Wind is pushing a huge rock towards me at with massive force at 2m/s. I push against the rock at equal force so the rock stays still. I am clearly "working" very hard, using a lot of ...
1
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1answer
39 views

Elementary proof of the minimum number or parameters needed to uniquely identify a force-torque (aka wrench) in 2D vs. 3D

Since the term force-torque (aka wrench vector) is probably more common in Robotics than in Physics, let's try to start with a definition of what is sought: a force-torque is a parsimonious set (well, ...
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1answer
25 views

Who is moving and with who's relation?

What if we are in a cube of 3×3 m  which is further enclosed in a sphere of radius 50 m? And the sphere start to rotate on its own axis would we experience force? If not then what happens if there is ...
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4answers
47 views

Who is said to do Work, me or the body?

If I subject my force to a body and it is displaced then the work is said to be done. What is that work done by? Is it said to be done by me or that body?
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0answers
28 views

Discernible “frequencies” of magnetic fields that do not affect each other

Two magnets secured to a surface close to each other in a fashion such that their constant attraction to one another is counteracted by the normal force of the securement of each. Is there a way to ...
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1answer
50 views

What happens when a high speed motor tries to drive a heavy car? High torque?

I'm trying to figure out what would happen if a really high speed motor - which has enough power to drive a car, but very high RPM & very low torque - tries to move a car. Does it get stuck ...
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1answer
68 views

What forces act on an object submerged in flowing fluid in an enclosed environment (i.e pipe)?

Let's say we have a pipe with water flowing through it and obstacle is inserted into the pipe and is rigidly fixed to the inner wall so that it does not get washed away. What forces are exerted by ...
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3answers
78 views

Air resistance force [closed]

How do I find the air resistance force and the maximum air resistance force when all I'm given is the mass, terminal velocity, and I know it's falling in quite air? I found a formula online but it ...
1
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1answer
68 views

When do we assume that a rope has different tensions in different places?

Working a problem with 2 pulleys and masses in class this week the professor at one point assumed that the tension on the two sides of a pulley would be different. Every other time we've done a ...
1
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1answer
29 views

Is the force of a lifting arm due to a piston an internal force?

When I was analyzing an excavator, I was wondering if the force that the piston exerts on the lifting arm is an internal or external force. I am a bit confused because the geometry of the system ...
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2answers
79 views

A simple pendulum

The idealized simple pendulum model (see the following figure) assumes that at every point of time the string to which the bob is attached exerts an equal and opposite force on the bob as does the ...
1
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2answers
127 views

Why do objects have resonance at natural frequency?

What actually is a natural frequency for an object and what makes it vibrate with increased amplitude when coupled with an external oscillator that matches the natural frequency?
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2answers
60 views

Direction of friction vector when acceleration is zero

There is a box on a ramp, there is Wx that makes it fall, Tension that pulls it up the ramp (a rope) and Friction. The thing is, how can I determine the direction of the friction? For me, friction ...
0
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1answer
30 views

Net tension with two opposite forces [duplicate]

What will be net tension if 10 newton force pull a body from opposite side.Will it be 10,20 or zero newton.
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0answers
19 views

Force and Advanced Physics: E.g. is gravity really a force? [duplicate]

I'm kinda beginner in physics but recently I've been studying really interesting concepts like the four fundamental forces and General Relativity. I started thinking that there is a weird ...
1
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1answer
20 views

Is there a generalized notion of intrinsic charges which describes a general interaction?

Consider classical fields. Lots of parallels can be drawn between different kinds of fields because they are fundamentally similar. Mass can be viewed as a mass charge, [charge] can be viewed as an ...
1
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1answer
47 views

Pendulum forces in orbit

On Earth a pendulum is governed by a set of equations, relating the angle of the swing, the mass etc. However with a pendulum in orbit there is no fixed point (assume 2 masses attached via a string). ...
1
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1answer
50 views

Why can contact force be ignored here?

I was discussing the first part of this question with a friend, and he told me that while taking moments about $A$ and $B$, we can ignore the reaction force at C. Indeed this is correct, because ...
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votes
1answer
82 views

How to draw the free body diagram of this? [closed]

There is a smooth light peg at C. The system is in equilibrium. The ground is rough. How do I draw the free body diagram for this? Here is the system, and my attempt.
0
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1answer
69 views

Is the force experienced by a particle influenced by its distance to the focus of the force? [closed]

Is the force experienced by a particle influenced by its distance to the focus of the force?
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0answers
42 views

Force in colliding snooker balls

If a snooker ball is traveling at 2m/s and hits another ball, the first ball will stop dead and the second will accelerate instantaneously to 2m/s. F=ma, so this would seem to imply an infinite force. ...
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2answers
72 views

How to calculate acceleration of the elevator? [closed]

A man of 80kg stands on a spring balance in an elevator. When it starts to move the scale reds 700N,calculate the acceleration of the elevator and identify the direction of the elevator
3
votes
4answers
856 views

Is the work done walking up an escalator in the same speed and opposite direction of the escalator zero?

Work equals force times distance, but what about walking up an escalator in the same speed and opposite direction of the escalator? In the frame of the ground, the distance is zero so the work must ...
1
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3answers
116 views

How is it that Force = Mass $\times$ Length / Time ^2?

I understand how $F=ma$ but what I am looking for is a diagram, idiom or concept that explains how force can be explained (in a partial layman's terms) as a combination of the dimensions; Length, Mass ...
0
votes
1answer
55 views

How the torque/moment-of-force can be mathematically defined?

Given the definition of torque/moment-of-force $\mathbf F$ applied in $P$ with respect to the pole $O$ $$ \mathbf M_O=\vec{OP}\times\mathbf F $$ and given that the vectors $\vec{OP}$ and $\mathbf F$ ...
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0answers
34 views

why do everything tend to be stable? [duplicate]

Whenever I ask'why does a proton attract electron?' People say that 'because they are oppositely charged' But I want to know why do opposite Charges attract each other and tend to become neutralised? ...
1
vote
1answer
36 views

Prove thrust is double the dynamic pressure across a nozzle

I'm trying to teach myself some of the content from 'Rocket Propulsion Elements' by George P. Sutton. After reading over the first couple of chapters feeling like I understood everything, I came ...
1
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0answers
56 views

How much energy does it take to hold a bag? [duplicate]

I'm holding a bag with some mass $m$. The force required for not letting it fall is equal to its weight $m \cdot g_L$ (where $g_L$ is the local gravity, assuming Earth this is $\approx 9.8 \; \text{m} ...
2
votes
1answer
91 views

Extension of Lami's theorem

I was experimenting with the triple scalar product and forces in equilibrium when I came to this result: Consider 4 forces $ \pmb{F_i}$ for $i=1,2,3,4$. $\pmb{F_i}=F_i\hat{e_i}$ where $\hat{e_i}$ is ...
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votes
1answer
37 views

Replace the force system with a single force [closed]

Please I need a quick answer I have an exam tomorrow