Laws Definition and 1000 Threads

Homework Statement A child pushes a block of wood with a mass of 0.72 kg across a smooth table. The block starts from a position of rest and after 2 seconds its has a velocity of 1.6 m/s [forward] The coefficient of friction is 0.64. a) Find the net force acting on the block of wood. b) Find...

I was looking at the Wikipedia page for Newton’s laws and read that they applied only to point particles. If we want to use F = ma on a larger object, if I read correctly, we must instead use Euler’s laws. I have a few questions about this. If this is correct why are we taught to use...

I have couple questions related to dimension and general physics law 1- Can we apply physics law in lower/higher dimensions. In another words does physics law makes sense in 2D or in 7D. 2- Is it possible that a 2D particle contains charge ? 3- Is it possible a 2D "object" exist in 3D ?

Hi, I had a thought recently which gave rise to a rather interesting query. A helicopter works and is able to fly due to Newton's third law of motion. The propellers rotate at a high speed and exert a force on the air beneath them. By N3L, the air therefore exerts an upwards force on the...

Here I have drawn the free-body diagram for a rock (but could really be any object) which is being pulled upwards. Fa represents the applied force (let's say...by a rope) Fg represents gravity/weight of the object Ff represents friciton, i.e. the small amount of air resistance But here's my...

Was just curious if there are any holes in the major laws of physics making them not consistent. Or could they change over time? And are they universal, as in, are they the same in all regions of the universe?

Hello there, I have a problem with this image from the Michelson Morley experiment in which one tries to calculate the time taken by the light beam to traverse the arm of interferometer perpendicular to the velocity of the frame in 'ether'. So the problem is, Are laws of reflection being...

Homework Statement The coefficient of friction between A and the table is μA. The coefficient of friction between A and B is μB. A, B, C and D all move with an acceleration of 2m/s^2 (A and B move to the left). Find the force that the friction between the bodies apply on B. Find the tension of...

Homework Statement No friction between m2 and M. The static friction between M and the floor is μs and the dynamic is μd. When F=0, what is the minimal static friction if M doesn't move? Homework Equations F=ma Force caused by friction: μN=F The Attempt at a Solution What I thought is that...

Here is an issue to distract the scientific mind for a restful Festive Season. This is a gumnut. They fall from trees round here (Perth, Western Australia) by the tonne. They are quite small (about 9 mm in diameter) and the pointy end is sharp. You do not want to stand on the pointy end...

Could huge amounts of energy change the universe's nature (fundamental physical constants, laws, dimension)? Could it change it so much that it would enable our universe to be a multiverse of level 1, 2, 3 or 4? https://en.wikipedia.org/wiki/Multiverse

Homework Statement The value displayed on the ampetmeter is 2A. The value displayed on the voltmeter is 5V Find the unknown ε and R Homework EquationsThe Attempt at a Solution I have the correct equations, I am sure of it. However on of them is: 2*2+2*10-ε-RI1=0 How do I know if RI1 (I1 is the...

Hello The following thought is confusing me a little. Let say we have sphererical planet with a certain mass and radius fixed in space. Now we have a point particle that at time t0 has a velocity vo that is perpendicular to the vector from the center of the plant to the particle and has a...

Homework Statement Homework Equations F = ma [/B]The Attempt at a Solution Why is the angle 60 degrees? Isn't it 30 degrees? [/B]

The invariance of the laws of physics in space-time is a corner stone of physics and all science. A.Is this an axiom or can be derived from other more fundamental axioms? B. Are there any books that discuss how science could be if the laws of physics could be changed (for example if we could...

Hello, I am taking physics (freshman, high school) and I am very confused on the current topic. We are learning about Newton's first, second and third laws. Our teacher speaks very fast and I cannot seem to understand many topics that he talks about. Questions I am confused on: 1. A plane is...

So, I was just working out on color and reflection but then turned a little bit confused. The main phenomenon we study everywhere is that a colored object absorbs light of all wavelengths excepting the light of its own color. Then comes the problem. As per that, if I beam a GREEN LASER on a RED...

1. The problem statement, all variables, and given/known data I am currently drafting a proposal for a project in Computational Physics. I'm planning on creating a program that simulates circuits numerically instead of solving the system of equations. The purpose of my project is to observe the...

Perhaps this is a simple question but I can't see a way to understand it. I have some expression of the form ##\ln(1-1/(1-x))## and I perform the following manipulations using simple algebra and laws of logs: $$\ln \left(1-\frac{1}{1-x}\right) = \ln \left(\frac{1-x-1}{1-x}\right) = \ln...

I need explanation of these formulas for polar coordinate system where position of an object is characterized by 2 vectors: r - from the origin to the object, and Φ - perpendicular to r, in the direction of rotation. https://drive.google.com/file/d/0ByKDaNybBn_eakJmS3dUVXVZUDA/view?usp=sharing...

You may know I started a thread on this forum asking questions about the statement in General Relativity that "the laws of nature are the same in inertial frames". Guessing about the answers I got, I arrived in the following conclusion. I'd like to know whether these make sense & are correct or...

This year, my state's governor signed into law requiring that windows are tested for tint in the annual vehicle safety inspection. The requirement for front windows in my state is 70% VLT. That is basically putting a layer of seran wrap on your window. I am a tinter and put 5% VLT (limo tint)...

Put here rather than in a computer forum because it is at the interface of computing and society. Many are familiar with Asimov's 3 Laws of Robotics: A robot may not injure a human being or, through inaction, allow a human being to come to harm A robot must obey the orders given it by human...

I believe that conservation laws, like for energy and momentum, are obeyed during the particle decay process, e.g. the total energy of the new output particles is equal to the energy of the one input particle. But is that relationship subject to quantum fuzziness? Suppose we, somehow, prepare...

Is it applying mathematics to a phenomena in the real world and create a model, test the implications of that model by manipulating the math, then checking that with observation and other established physical laws. If it doesn't match up, then a new model is required or another type of...

Hey. I have watched a video byMIT explaining the Newton laws. I have however a question. I learned that The Force that object 1 has on object two is equal to the force object 2 has on object 1. In an example with a collusion between a train and a marble we were told that the force is equal to...

Homework Statement [/B]Homework EquationsThe Attempt at a Solution I really have no idea how to proceed. Applying Kirchoff's laws to this would be quite lengthy. This circuit is supposed to be a wheatstone bridge but I can't see it.

It is not the laws of physics, but the forms of laws of physics which are the same in all inertial frames. Comment."The forms of laws of physics are the same in all inertial frames" is a necessary condition (put by scientists ) to get satisfied by something which has to be called as a law of...

Homework Statement Discuss how Newton’s Laws can be used to explain the introduction of transportation safety features such as: Speed Limits on curved ramps Homework Equations Newton's 2nd Law: F=ma The Attempt at a Solution I believe that according to Newton's first law objects that are in...

Homework Statement A child stands near the middle of a roundabout that is rotating with some angular velocity w. The child moves towards the edge of the roundabout in a straight line from the child's perspective and at constant speed. Explain in as much detail as you can (and using equations)...

Hi, While solving homework problems, I start by defining a positive-y direction and a positive-x direction. Let's say up and to the right. Until now, I've applied this same rule to all objects in each problem, no matter the direction the object moves. But it seems I have not understood this...

Homework Statement A student is cleaning a block board by moving a light duster up and down as shown. (Coefficient of friction between the duster and board is ##MU## The duster will not move no matter how large the force is if ? Homework Equations No equations given The Attempt at a Solution...

Homework Statement Determine the speed with which block B rises in figures if the end of cord at A is pulled down with a speed of 2ms^-1 Homework Equations Given Velocity downwards at A=2m/s The Attempt at a Solution Really stuck... Couldn't even start the question solving...I know all...

Homework Statement In the situation given all surfaces are friction less pulley is ideal and steering is light. Find accn of block 2 Homework Equations Given F=mg/2 The Attempt at a Solution .[/B] Got answer as G/2 instead of G/4 ...(actual answer is g/4) Since F=mg/2 and block 1 is hanging...

Homework Statement In the following diagram a massless pulley is pulled by a constant force of magnitude P. There is no friction between the block and the floor. The acceleration produced in the block if mass m is? PIC ATTACHED Homework Equations Took a1/2=a2 where a1 is accn of block and a2...

It is often told that fundamental laws are insensitive to +t/-t change. Let's try this one: a little mass m1 object is accelerating towards a big object M2, in -x direction in space and +t in time, due to gravity or following space-time free fall line (along a geodetic). Now, revert the video...

The electromagnetic wave equation being of the same form in all intertial frames is because Newton's force is a vector quantity? I mean, if the wave equation changes its form from a intertial frame to another one, would the electromagnetic force be different in the two frames? I know that one...

Homework Statement In the circuit shown in the figure (attached with the solution). Determine: 1. the reading of the ammeter when the key (K) is open. 2. The reading of the ammeter when the key (K) is closed. Homework EquationsThe Attempt at a Solution [/B] What confuses me in the circuit...

For an experiment we configured three 6V solar panels in parallel connected to a 10 ohm resistor. Each panels outputs roughly 0.5A each (measured) so that's 1.5A through the resistor. But the voltage across the resistor measure 15V. Does anyone know why this happened?

I've heard it said multiple times on here and elsewhere that as we "wind back the clock" of our Universe and the Big Bang that our laws of physics kind of begin to fall apart, in a sense. If this is true, can anyone explain exactly which laws become more difficult to work with, and why? Thanks.

We were asked to do an experiment where we had to prove the equation: T2=(4π2m)/Mgr Where M is the mass of the mass stack in kg (0.3kg), m is the mass of the rubber bung in kg (0.0226kg), T is the time taken for one rotation in seconds, r is the horizontal radius of rotation in meters, and g is...

Homework Statement Why is the formula ##p = \frac{1}{3}\rho<c^2>## used to calculate the mean square speed at 273K? Why 273K?

< Mentor Note -- thread moved to the EE forum from the Homework forums since it is a more general set of questions >[/color] So, we are going into Kirchhoff's Laws in class, and my entire understanding of circuits, which took me a while to form, is again falling apart. A physical understanding...

Question (see attached diagram): PV diagram with 7.5 moles of ideal diatomic gas through cycle a, b and c. What is the highest temperature reached by the gas during the cycle? (multiple choice answers 180, 325, 208 and 100 C, i know answer is 208 C but I'm not getting it!) It is a PV diagram...

From Odum (Father of modern ecology) Ecosystem follows the laws of termodynamics 1st law 2nd law The way the laws have been put it looks alright but they are valid for closed systems only which ecosystems are not. However according to wikipedia apart from having a closed system there are...

When a keep two blocks one over another...And apply a foce on the block which is below...Why does the upper block falls down..Why dosent it move with A? assumin there's no friction between A and B?

Do laws of physics apply below the event horizon? It appears as if black holes had such gravity as to have an escapr velocity higher than c, which means that things are pulled inwards at higher speeds than the speed of light. Or am I overlooking something?

So it seems there is predilection in physics to go after simple and elegant models of physical reality. That is, parsimonious models are preferred. Sometimes this means that there is a trade off between mathematical elegance and intuition. For example, if theory A and theory B both perfectly...

Not saying that there is another universe. But if there were, would the laws be the same? I've heard Leonard Susskind explain that extraneous solutions of string theory could represent the environment in regions very far "away". So is it just small things like the physical constants being...

Homework Statement [/B] A boy with a mass of m1 is sitting in a carousel. The spinning frequency is 0.3355. The boy is also sitting on a weighing scale, will they show a number higher than m1g,lower or the same? (The mass of the weighing scale is 0). Homework Equations mω2r=F ma=F ω2=4π2f2...