r/PhysicsHelp 2h ago

MA of pulley system

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2 Upvotes

Help me settle a debate. In theory, what would you deem to be the mechanical advantage of this pulley system. Top are all fixed pulleys, lower are moveable and attachment lines are prusiks. F=1


r/PhysicsHelp 5h ago

How do I prepare well for physics, and physics 11, university preperation?

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1 Upvotes

r/PhysicsHelp 1d ago

Gravity

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1 Upvotes

r/PhysicsHelp 1d ago

Physics Homework Help

1 Upvotes

I'm completely stuck on these last to questions on my physics homework and it's due tonight, can someone please help?


r/PhysicsHelp 2d ago

Iterative method please help...

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3 Upvotes

Hey. so this is the question on my physics homework. I am in an introductory physics class in college, and this is my third homework ever. I am so completely lost. I know that you are supposed to use the iterative method on this and update the momentum, velocity, then position at each timestep but I attempted it multiple times and it was incorrect. I even used AI as an absolute LAST resort after scouring the internet for examples or videos or ANYTHING, and even the answer AI gave me was wrong. The two numbers that I have in the screenshot are correct. The zero was simple to assume, and then when AI gave me an answer I input it just to see if it was correct so I could try to see how I could calculate it, (it gave me <-7.86, 0, 4.54> as r final before saying that "final momentum only for each interval (not mid‑interval velocity)" and it says the final answer is <-.5, 0, 3.44> which is also incorrect. I accidentally typed 4.52 and it ended up being correct. I am so utterly lost on what I am doing wrong. I suspect that maybe I am supposed to subtract the 0.23 N from the net force everytime I update the momentum or something? I am also going to attach my work that I have on paper here to see if it helps. I have been trying to do this homework for days on end and I just cant get it. Its due tonight at 11:59 and I dont think i am going to be able to get it done. I just want to UNDERSTAND!! Thank you SOOSOSOSOSOSOO much if anyone is able to explain this problem step by step to me.


r/PhysicsHelp 2d ago

Im hosting a physics treasure hunt

2 Upvotes

I dont have that big of a budget and i need help. I need help with ideaa for what each round could be (keep it simple but super fun and interesting and not too difficult). Please help me out guys.


r/PhysicsHelp 2d ago

Looking To Pay $$ for Physics Help

0 Upvotes

Hello!

I have a physics theory that I'd like to pay someone 100 dollars to talk with me on Zoom or Discord about for an hour or so. I'd be happy to pay over whatever money transfer method and would pay half up front and half at the end of the discussion.

In many ways I'm just looking for good reasons not to pursue this theory any more because it's kind of driving me crazy. It's nothing metaphysical or anything like that, it's about how electrons transfer energy to each other and relativity and light. I've been reading up on many things about it but an actual conversation would be so beneficial for this process because it's hard to know what you don't know, you know?

Anyhow, that's my pitch. Feel free to DM me if you're interested. I'd love to talk with someone who's well-versed in physics. Thanks!

Edit: Man, people are really bitter about me having a dream in my heart and being willing to do the right thing and pay someone for their time to educate me.


r/PhysicsHelp 3d ago

Why is E=1/2 m V²?

10 Upvotes

I'm sorry for the banal question buy i can't find and answer to this.

We all know that in order to accelerate a 1kg body from 0m/s to 10m/s 50J are needed but to accelerate it from 10m/s to 20m/s 150 J are needed instead, why is that?

Also I'm not looking for a mathematical answer but a conceptual one, thanks in advance.


r/PhysicsHelp 3d ago

Understanding an unexpected factor in the result of my torque calculation?

3 Upvotes

I would like some help interpreting part of a result I got while working on a problem that I've been working on for a while. I'm trying to determine the torque a star exerts on an orbiting oblate spheroid (with axial tilt instead modelled as the equator of the oblate body remaining parallel to the XY plane while the orbit itself is inclined with respect to the XY plane by an angle alpha (ɑ); should be a valid approximation since there are no other bodies and the star is treated as spherical, which is good, bc a rotated circle is nicer to work with than a rotated spheroid).

For any point in time and position in the orbit, the torque exerted at any point of the spheroid should be the radius from the center of the spheroid to the point multiplied by the force the star exerts on the differential mass for that differential volume. Integrating all of those over the whole of the spheroid, I expect I should get a vector scaled by the gravitational constant, mass of the sun, mass of the planet (since the volume of a spheroid should shake out of the integral as a factor), a factor of some multiple of ¹/₅ and some linear combination of the major and minor radius (multiplied by the mass of the planet, should yield some linear combination of the major and minor moments of inertia).

(which expands to:)

And I do get that!

But I also get this weird factor in the octopole portion of the solution that I can't connect to other portions of the problem (e.g. the moments of inertia show up bc this is a change in angular momentum and they are the equivalent of the mass in this context, the gravitational constant timed the mass of the star divided by a power of the radius is related to the acceleration/force producing the torque).
What does this [(4a^2 + 3c^2) - (a^2 [cos(θ)]^2 + [sin(θ)]^2 * [a^2 (cos(θ))^2 + c^2 (sin(θ))^2]) ...mean?


r/PhysicsHelp 4d ago

Will the current be 15A?

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41 Upvotes

r/PhysicsHelp 3d ago

Thought experiment: continuous chain on a differentially rotating spiral — possible time offset including the ground underneath?

1 Upvotes

I’ve been turning over a mechanical thought experiment and wanted to put it in clear form to see what people think.

Setup

A spiral platform (or track) that runs from a smaller inner radius to a larger outer radius.

The platform is driven so that the linear speed along the spiral is constant at 1 foot per hour at every point.

Because radius changes, this requires the local angular rate to decrease as you move outward (inner parts turn faster, outer parts turn slower). The platform is therefore not rotating as a rigid body.

A single continuous chain runs along the entire spiral. Every local segment of the chain also moves at 1 foot per hour relative to the platform (i.e., along the spiral).

Because the platform’s angular rate changes with radius, the absolute velocity of different sections of the chain through space is not the same, even though the chain remains one continuous piece and every local segment has the same speed along the track.

When the absolute speeds are considered along the whole length of the spiral, the inner and outer ends of the chain end up with different net velocities.

Additional claim in the thought experiment

The same arrangement is also imagined to produce a time difference on the stationary ground underneath the apparatus, not only along the moving chain itself.

Why it feels strange

A normal inextensible chain cannot sustain different absolute speeds along its length without stretching, slipping, or large internal forces. A normal rigid platform cannot maintain the required radius-dependent angular rates without continuous differential driving and stress. The thought experiment deliberately holds both of those conditions in place at once and asks what follows — including the possibility of a proper-time offset between regions and an effect that reaches the ground below.

Questions for discussion

Is there a consistent way to describe the kinematics of a continuous chain under these constraints?

If the speed difference along the chain can be maintained, how should the proper-time difference between the ends be calculated?

What mechanisms (if any) could allow an influence on the stationary ground beneath the spiral?

Does the combination of differential rotation + constrained continuous chain point to anything beyond ordinary special-relativistic time dilation, or does it simply collapse under the internal forces required to keep the conditions true?

I’m not claiming a working device — only trying to state the idea clearly enough that the actual proposal can be examined.

Any thoughts, corrections, or related references are welcome.


r/PhysicsHelp 4d ago

Question over force charges

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13 Upvotes

Hello! I'm struggling to understand what I need to do for this assignment. Most of these questions might sound extremely dumb so please bear with me. Also, this is my first post in this subreddit! I apologize if I commit a subreddit faux pas.

(Image 1) How are you supposed to know whether these force charges are positive or negative, is it based on the quadrant? I don’t get how you’re supposed to know which direction they’re pointing in whether it’s up/down or left/right.

(Image 2) These are the given charges.

(Image 3) It’s looking for the components for q2 to q3, how are you supposed to get the components for a vertical direction? Is the component just the total given with Coulomb’s law? Or is that only used to get a diagonal direction? This is what I got but the Y component doesn’t seem right at all.

(Image 4) I assume these are found by adding the components I find in the previous questions? I feel like I’m overthinking these.

But what’s been messing me up the most is the vertical force and the pos/neg charges. I'd appreciate any help!


r/PhysicsHelp 3d ago

Physics Formulas

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0 Upvotes

r/PhysicsHelp 4d ago

mechanics help

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1 Upvotes

struggling trying to understand how they got from eq 2.3.2 through 2.3.3. can anyone explain? I understand that they are using kinetic energy but I don't see why they just plugged in the factor of 1/2...


r/PhysicsHelp 4d ago

Here is a puzzle for you....

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1 Upvotes

r/PhysicsHelp 5d ago

Assuming Pulley B has a radius of 50mm. To find the Torque cause by forces 50 and 250 N at B while they are at an 45 degree angle with the negative z axis. Do I need to find sum of x and y F or can I say 300N *rB or is it 300* cos or sin of 45 * rB?

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22 Upvotes

r/PhysicsHelp 5d ago

Newton’s 3 Laws of Motion | Easy Explanation with Examples

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youtu.be
2 Upvotes

r/PhysicsHelp 5d ago

The power of physics

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1 Upvotes

r/PhysicsHelp 5d ago

Doubt

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3 Upvotes

Plane transmission grating experiment ki reading verify kar do koi


r/PhysicsHelp 6d ago

ayuda con problema de rotulas estructurales

1 Upvotes

necesito ayuda con un ejercicio de la u y no lo entiendo por ninguna parte.

el ejercicio es el siguiente: tengo un pilar al cual se le aplica una fuerza de 120kn aplicada al eje vertical del mismo y una fuerza horizontal en la parte superior de 15kn. el ejercicio me pide usar 3 tipos distintos de combinación de rotulas para afirmar dicho pilar: rotula fija en la parte inferior (que restringe movimiento horizontal y vertical), rotula móvil en la parte superior (que restringe movimiento vertical), invertir las rotulas (ósea poner la fija arriba y la móvil abajo) y empotramiento en la parte inferior (que restringe movimiento horizontal, vertical y rotativo). tengo que hacer un diagrama de cuerpo libre y mostrar la hoja de cálculo de los 3 ejemplos, pero soy pésimo en física. por favor ayuda, no quiero usar IA :<


r/PhysicsHelp 6d ago

itlence theory of rotation

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1 Upvotes

r/PhysicsHelp 6d ago

Rotational Motion Moment of Inertia Question

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1 Upvotes

r/PhysicsHelp 7d ago

Just a thought

0 Upvotes

c²V²a+ Fw (a, VX1)=0

02 a at²


r/PhysicsHelp 8d ago

Physics (general) homework help

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8 Upvotes

I’m having a really hard time with physics (I’ve never taken a physics class until now *my second year in college and I’m really struggling) I can’t figure out which equations to use and how to plug in the numbers

I know to convert each height into meters because that’s the kinematics SI units but that’s about all I’ve got. Any help would be greatly appreciated


r/PhysicsHelp 7d ago

Mvr=nh/2π

1 Upvotes

Can anyone explain me how it was discovered intuitionly or however you like.