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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Unit for Impact Force

Forgive me if this is a newb question but I am not a trained scientist, much less a physicist. I'm just curious and would like to know if there's a unit to measure impact force. I know the newton is ...
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1answer
383 views

Where are the centers of mass for a baseball bat vs. a cricket bat?

My friend and I were comparing the rightness of a cricket bat versus a baseball bat for general violence purposes. (Eg, rioting.) Where are the centers of mass for these two instruments? Which would ...
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1answer
198 views

determine temperature at which pita bread will expand in a toaster

suppose you have a pita pocket of radius 5cm or .05m. We will model the pita pocket as consisting of disk with a layer of air of volume V which is contained by the surface of the bread. We will ...
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1answer
135 views

3 current loops with non-conservation of momentum, when one specifically considers SIGNs

Thought experiment I. Consider two loops of wire, 2 small dipoles B and C , with a common axis z (facing each other) and (say) 30 cm apart B to C. At the speed of light, information (including a ...
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4answers
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How far does a trampoline vertically deform based on the mass of the object?

If a baseball is dropped on a trampoline, the point under the object will move a certain distance downward before starting to travel upward again. If a bowling ball is dropped, it will deform further ...
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2answers
425 views

Force exerted by rotating bar

Say we have a bar immersed in liquid, and that the bar in being rotated at a given constant angular speed. What force is exerted on the liquid by the faces of the bar moving through the liquid (so the ...
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2answers
996 views

Solve spring system

I am not physics in training so if anything is unclear please request clarification. I have a set of objects to be placed on a line, linked with springs of known lengths (L) and stiffnesses (K). I ...
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2answers
386 views

Problem with forces acting upon a sloped plane

We have a structure that is sloped at 20 Degrees to the horizontal and weights 160N. We then have a force (wind) which is acting along the horizontal plane which has been calculated to be of about ...
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2answers
903 views

What, if anything, makes forces the “cause” and acceleration the “effect”? [closed]

We typically say that forces cause acceleration inversely proportionate to mass. Would it be any less correct to say that acceleration causes forces proportionate to mass? Why? (Note that the ...
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3answers
195 views

Constrained particles under distance dependent force

This question is from the 1975 Canadian Association of Physicists Exam. No solutions are posted and I am quite lost on how to proceed with it. A particle is constrained to move along the x-axis of a ...
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1answer
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calculating thermal energy [exam prep]

I'm preparing for a grade 11 physics exam but having trouble with a question: a 19.9kg mass slides in a straight 28.8m line experiencing friction with a coefficient of 0.105, how much thermal energy ...
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4answers
872 views

What do we consider “Perpetual Motion”

I know this is a bad question to most serious Physics but I have a question about what is considered “Perpetual motion.” The Foucault pendulum in the UN consists of sphere that passes directly over a ...
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1answer
287 views

Stresses put through joints on a steel climbing wall

Being a fan of stackoverflow, I thought I could try this question here, hope its not too off topic. I'm wanting to build a free standing climbing wall in my garden and dont know where to start ...
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2answers
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Can someone explain the physics of a standing jump?

I would like to use something like a kinematic equation to know where the person will be in the jump at a given time. However since I think acceleration is not constant because of the jump force it ...
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1answer
183 views

Paramagnetism what about Paraweakism or Parastrongism?

Ok, I was just curious but the electromagnetic force can allow paramagnetism macroscopically in some objects. Can this be done microscopically to the subatomic level? Also, what about other forces ...
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2answers
497 views

Would a car tow rope withhold an adult person?

I am not exactly sure how the physics work here. If we take a car tow rope, which is manufactured for towing a 3500 kg car and we actually start towing such a car on this rope, what force do we really ...
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3answers
301 views

Action - Reaction pair, through photons

Here's an example to describe the issue Supossed a high power laser (eg a 100 kW laser, ie, electromagnetic weapons) is fired to a target, then it will receive energy and move. (and likely to burn or ...
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3answers
504 views

Why trimming the mainsail gives a larger torque to head up

I am learning sailing on a 5m catamaran (Nacra 5). I am familiar with basic aerodynamics and the physics of the sail and keel. We learned that when sailing closed hauled, too tight a mainsail tends ...
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1answer
397 views

if a force is 1 newton metre, what is it at 2 meters?

If I have a force, say 24 kg/cm what would that equate to at 2cm? I would like to know the formulae for calculating this. For example. If a motor can hold an object of 24kg at 1cm from its pivot ...
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6answers
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Which person can handle falls from big heights better: lighter or heavier?

This probably includes a little of biology, but I believe it's mainly physics, so I hope it's ok to ask here: Imagine 2 persons: Person A weights 120 pounds and person B weights 180 pounds. Imagine ...
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1answer
522 views

Acceleration Force [closed]

A 6500-kg helicopter accelerates upward at 0.60 m/s² while lifting a 1200-kg car. (a) What is the lift force exerted by the air on the rotors? (b) What is the tension in the cable (ignore its mass) ...
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2answers
2k views

Distribution of forces

(little background: I'm trying to develop a small, quick 'n dirty static physics engine to determine whether a stacking of boxes is stable). If I have a 3D rigid box (with the bottom in the ...
2
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4answers
271 views

Rocket engine, perpendicular to the end of stick, in space

Rocket engine, perpendicular to the end of stick, located in cosmos, without atmosphere and gravitation. As in picture below: In what direction will the stick move? In V or another direction?
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2answers
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What is the force on the arms in a pushup?

What force do the arms have to generate to do a pushup? Let us look a this simplified model: The body can be represented by the green plank of mass B. Its angle to the ground is $\theta$. This ...
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3answers
212 views

Making a “heavier-than-air” craft float

How big would a hollow rigid object need to be to float, (not in water but in air) if all of the air was vacuumed out and the container sealed?
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1answer
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Basic explosion physics - determining force

I'm using a game engine that has a ton of physics stuff built in. What I am currently trying to do is to simulation an explosion with F force in an x,y coordinate system and figure out how other items ...
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1answer
154 views

Spilling a cup of coffee

I've observed this many times when I spill coffee, It gets attracted towards the cup or the vessel. why is this so? Which is the force acting? (Hope you understood my question).
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Forces in a Pendulum

Help me visualise the forces found in a pendulum. I know weight can be decomposed into $F_x$ and $F_y$. Centripetal force, acceleration and velocity are three words that I'm confused. Centripetal ...
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2answers
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Strongest force in nature

Possible Duplicate: What does it mean to say “Gravity is the weakest of the forces”? It is said nuclear force is the strongest force in nature.. But it is not true near a black ...
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3answers
1k views

Optimal technique to tear perforated paper along the perforation [closed]

My daughter's coloring book has perforated pages, so you can easily rip out the pages for easier coloring action. Great. Trouble is, the perforation isn't enough, and it's almost impossible to rip ...
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0answers
233 views

The physics of two circles colliding [duplicate]

Possible Duplicate: Physics of simple collisions I have looked around the internet and gradually built up a better understanding. However I'm still not 100% clear on the physics. If I have ...
2
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2answers
535 views

Homework about spinning top [closed]

I have a top of unknown mass that has a moment of inertia $I=4\times 10^{-7} kg \cdot m^2$. A string is wrapped around the top and pulls it so that its tension is kept at 5.57 N for a distance of .8 ...
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4answers
1k views

How many fundamental forces could there be?

We’re told that ‘all forces are gauge forces’. The process seems to start with the Lagrangian corresponding to a particle-type, then the application of a local gauge symmetry leading to the emergence ...
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2answers
638 views

Forces on a simple flat slope [closed]

This diagram is of a block (b) moving down a ramp unaided. Taking gravity (g) as $9.8ms^{-2}$, and the mass of the block (b) as $0.2kg$, how can I find the force acting along the slope (f). BTW: ...
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1answer
3k views

Find velocity and displacement from force equation

How to find velocity and displacement equations from a given force equation? For instance, it was given the following 1-D equation: $$F = b_1(v_1-v) - b_2 v$$ $v_1$, $b_1$ and $b_2$ are constants. ...
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4answers
2k views

Gravitational force between two masses

I get it that there will be a gravitational force between objects attracted towards gravity but can there be a gravitational force between two objects resting on horizontal plane? In other words, does ...
5
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4answers
297 views

When displacement isn't possible

Stop me if i'm wrong but displacement is, for example, when you enter a bathtub the water level rises around you. What happens when displacement isnt possible? I'll give an example. I have two ...
5
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2answers
643 views

Tricky spring on a surface question

I have this relative simple-looking question that I haven't been able to solve for hours now, it's one of those questions that just drive you nuts if you don't know how to do it. This is the scenario: ...
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6answers
607 views

Is it possible to throw an object faster but over the same distance?

Is it possible to throw say a tennis ball at $1ms^{-1}$ for 20m and then be able to throw the same ball at $2ms^{-1}$ for 20m at the same angle? That is throwing the ball in a traditional curve withe ...
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5answers
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How much force would be necessary to hold a 6-foot steel staff weighing 20 lbs from one end of it, parallel to the floor?

This isn't a homework problem. I'm asking cause I'm wondering how strong a person would have to be to pull it off. Their arms would be extended, both hands gripping the staff at one end, and the staff ...
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3answers
269 views

A force's magnitude

In this question I asked about gravity and in the answers it came up that the magnitude is equal (of the gravity acting on the Sun and the of the gravity acting on the Earth) Does magnitude simply ...