Force Definition and 1000 Threads

Trolley should have zero acceleration.

Hi All, My question is in relation to forces that can come through movement. For example, the skull is stated to take around 520 pounds of force or around 2000N: https://www.virginialeenlaw.com/help/how-much-force-can-a-human-skull-withstand.html However, boxers can punch well in excess of...

Well known examples of the force produced by pressurized water exiting a pipe: JetLev Water Propeled jet Pack. Hovering Car. I need to calculate the maximum for the thrust produced when the hose or pipe is bent rearward. Since this is similar to the case of a water bottle rocket, the guess...

According to this link here https://en.wikipedia.org/wiki/Relativistic_mechanics#Force , we can inverse the relation of force in terms of velocity and acceleration: $$ \mathbf{F} = \frac{m\gamma^3}{c^2}(\mathbf{v} \cdot \mathbf{a})\mathbf{v} + m\gamma\mathbf{a} $$ to get: $$ \mathbf{a} =...

Hi, The problem I am working on requires me to work out the the pressure on the outer conductor of a coaxial cable due to the current on the inner one. This cable carries a dc current of 5000 Amps on the inner wire of radius 2 cm. The outer cylindrical wire of radius 5cm carries the return...

The total energy of the particle is ##u^2 / 2 - k/R##. When ##u^2 \gg 2k/R##, we take the total energy to be ##u^2/2## only. By the conservation of energy, we have: $$ \frac{u^2}{2} = \frac{w^2}{2} - \frac{k}{p} $$ Take the angular momentum expression ##l = bu##, we can replace ##u## with...

Hi, I'm currently looking into the forces exerted on a cable if the cable was to go from slack to taut due to a falling object that is pivoted about a lower hinge - such as a drawbridge but instead of slowly lowering, there is slack in the cable causing the bridge to freely rotate about the...

Image above is the question. Below image depicts solution. if F1 is removed then the acceleration of that mass must be sum of accelerations of remaining forces. Right?? But answer says that acceleration of that mass is equal to acceleration of F1. I don't understand it. Can someone explain it??

Just to be clear, this isn't a homework problem. it is an example problem found on page 68 of the text "Matter and Interactions" 4th edition. The solution is given in the book, but I'm having difficulty following their reasoning. according to the book the net force is not constant, therefore we...

Hi all, I was thinking punching a round ball on a flat surface and seeing how I could determine a formula for force from it. I thought the following: 1. The ball will go further the harder I punch and thus force must be proportional to displacement d. 2. Ball will go further if it is lighter...

$$\sum_i m_ir_i$$ Why the term always vanishes? There's some more equations where the mr was vanished. But, they didn't explain why it vanish. Why the term vanish? I think that's for position 0,isn't it?

In Q.E.D., the electrical part of the Lorentz Force between unlike and like charged particles is realized through the absorption and emission of photons. How is the magnetic part of the Lorentz Force realized in Q.E.D. via photon activity? As always, thanks in advance.

Solution 1: Force on air = Force on helicopter. ##F = \frac {dp} {dt} = v \frac {dm} {dt} = v^2 \rho A## ##P = Fv = \rho A v^3## Solution 2: Power from helicopter converted to rate of kinetic energy increase of air ##P = \frac {dE} {dt} = \frac {1} {2} v^2 \frac {dm} {dt} = \frac 1 2 \rho A...

><br/> >Mass M1 is held on a plane with inclination angle θ, and mass M2 hangs over the side. The two masses are connected by a massless string...

For a case of electrostatic field (B is equal zero), how should the force acting on a moving charge be calculated if we want to take into account all the relativistic effects? Also would it be correct to calculate the acceleration of the charge as a=F/m, or should some other formula be used? For...

Good morning everyone! I am an aerospace engineering working on my thesis and i am trying to solve a little problem. In the picture you can see an "aeordynamic" body. The CFD analysis gives me the forces and the moments acting on this body. How can i calculate the momentum acting on the body...

Hello In a pharmaceutical lab,a certain pressure is applied to IV bags using the equipment shown below.We need to calculate the force acting on the bags based on the applied pressure.I know the formula is F=PxA.But i am not sure what the surface area is.Should i take the whole surface area of...

I am an Engineer, so I have some knowledge about physics and calculus. I've seen relativity in university years ago but only briefly. The majority of my knowledge in SR and GR, which isn't much, are from reading, studying and searching online myself. I have seen some definitions that I am not...

[Moderator's note: Spin-off posts from previous thread have been included in this new thread. Also, the OP's re-post of the scenario for discussion has been moved to this top post for clarity.] Yes. Physically, scales measure a force (and indirectly the energy) in their frame. Consider the...

When I read things about magnetism on internet, I don't understand at all about one thing: If a moving particle receive a force if it's in a magnetic field, so it should accelerate, so what happen if we change the referential so that the particle now don't move? The particle shouldn't receive...

In the following page (which, despite examining a question that comes up in science fiction, raises valid scientific questions): http://pages.erau.edu/~andrewsa/sci_fi_projects_spring_2015/Project_1/Eilts_Mitchell/Enders%20Game%20Eilts/Enders%20Game%20Eilts/index_Eilts.html I encountered the...

I know that the ##F_{AonB} = -F_{BonA}##, but I just wanted to check something. If object A is the truck, then the x-direction should have a vector coming from the force of the engine driving the truck forward, a vector pointing in the negative direction for friction, and a vector in the...

I have figured out how the force is towards left in the first case. I think it is due to the larger force on - charge. Please help me out with the second and third case.

In considering the excellent answers given to my previous query about a photon in a box, I was led to consider what force was needed to hold the walls of the box stationary (w.r.t. an inertial observer inside the box.). If you place a mass m on the end of a very long string of inextensible...

I have jus thought about how maybe I could sue the magnetic field strength equation for a solenoid (that I used to find the Emf in the first place) again, to find the magnetic field strength arising from the induced current: B= μNI / L where μ is the permativity of free space N= Number of...

Hello, i´ve got a problem with the calculation of the forces on the hitch of a vehicle and a trailer. I do need the lateral force on the hitch for the calculation of my single track model of the vehicle and trailer. I have a longitudinal model of the vehicle and the trailer. My input signal...

I weight 90.7kg. I fell 10.05m landing on soild concrete. how do I express the "power of my impact? in G-force? A relitive weight? I am self taught in very basic physics after a high school education.

And if a star is severely stretched by tidal force, how does that affect its magnetic field and the process of it collapsing at the start of a supernova?

There is a tall cylinder filled with water. And there is a 3 in diameter hole near the bottom and water is gushing out. (assume the cylinder is continually being re-filled from the top) You work to plug the hole with a 10 inch long cylinder that is exactly the perfect diameter fit to plug the...

As the force on a pulley is equal to twice the tension, I just have to find the tension to solve part A. To do so, I first wrote the equations for both m1 and m2. m1 * a = T - m1g m2 * a = T + N - m2g The tension must have the same values for both equations so I added both equations to find...

The summary refers, for example, to the Wikipedia explanation "The force results from a transient shift in electron density. Specifically, the electron density may temporarily shift more greatly to one side of the nucleus. This generates a transient charge to which a nearby atom can be either...

I am having trouble coming up with a FBD. I know there is a Fg, Fn, friction, and applied force on the masses, but would there be another force going upwards because of the acceleration?

As I understand it, when a body undergoes uniform circular motion its velocity does not change in magnitude but instead direction. This change in velocity, or acceleration, is directed inward towards the center of the circle. If a body was not experiencing a net centripetal acceleration, then...

I tried just calculating the force with Coulomb's law, then calculating the forces for each vector individually and adding, but I got it wrong both ways

Hello, as you can see i am trying to understand conceptually how the tires during turning create a centripetal force. It was explained to me that as we turn the car tires, the tires similar to a ski or a wedge, now want to push the ground to the side and forward. If the ground was loose, this...

qn3: why is statement 2 the only answer? isn't speed one of the factors in velocity too? then shouldn't statement 1 be true too?

I feel that its M because as the conductor moves upwards, towards K, an equal but opposite force will be produced at M to pull the conductor downwards, but answer is K.

I feel that its M because as the conductor moves upwards, towards K, an equal but opposite force will be produced at M to pull the conductor downwards, but answer is K.

OK. Gravity is not a force it is a contraction or curvature of space. I was free-falling and now I hit the ground. Why don't I float through the universe, or go upward instead of still trying to go downward. Because I hit the ground, and now there is no force(like gravity) and my free-falling...

Let's assume I have a ball moving at a constant velocity and it collides with a spring and the spring compresses n cm. If I know how much mass the ball has and the spring constant D, how would I calculate the Force? I mean since F = dp/dt I would have to know the time in which the stopping...

I'm having issues in the application of tire forces while deriving a multi-body model of a motorcycle via Lagrange. In particular, I considered several bodies that are: swingarm, main frame, front upper fork, front lower fork and wheels. I suppose the wheels to have zero slippage, then...

Hello all, I am trying to understand how a force at the opposite wall from water entering a pressurized air (atmospheric pressure) tank, and for this discussion it is rigid, with no relief valve to displace the compressed air can be deduced. I have created a simple illustration and believe this...

Hello everyone, I was curious about how do we define a physical quantity and mathematical relation between them. For example: Work done is defined as product of force along the displacement and displacement i.e W=Fcos(theta)d. Now this definition is given in books straightforward but my...

Hello . The goal is to look for what force F I need to apply in order to return the arms to the closed position. Attached is a schema in the hope that my purpose will be understood I want to know what forces are acting on the system of the arms as well as the springs Many thanks in advance

If the statement above is correct, I do not understand this concept. I guess by charging my phone I am not producing matter. Does it mean in this case, energy converts to mass (not matter)? Can someone please explain this?

If I have a force that behaves according to the formula ##F(x)=\alpha x-\beta x^3##, how can I get the potential energy from it? I know that: $$-\frac{\mathrm{d}V(x)}{\mathrm{d}x}=F(x),$$ but what about the limits of the integration?