What is Change: Definition and 1000 Discussions

When an object (e.g. racecar) moves around in circles with constant tangential velocity, constant centripetal acceleration is present. What happens to the centripetal acceleration when the racecar is at rest, then increases its speed? I know that the tangential velocity increases due to the...

Homework Statement How much energy must be removed from the system to turn liquid copper of mass 1.5kg at 1083 degrees celsius to solid copper at 1000 degrees celsius? a. -2.49X10^5J b. -3.67X10^4J c. 2.25X10^3J d. 9.45X10^4J e. -2.78X10^3J Homework Equations Q=Mc(Tf-Ti)...

1. The problem statement. A tennis ball of mass m moving horizontally with speed u strikes a vertical tennis racket. The ball bounces back with horizontal speed v. Homework Equations p = mv The Attempt at a Solution My answer was m(v-u), meaning the final momentum (mv) subtracted from the...

This is an inquiry about some of the details of the bending of the trajectory if a photon by curved space-time (S-T) from the perspective of general relativity (GR). The environment in this scenario contains a black hole at its center, a photon passing by the black hole a km above the event...

Anyone know how to change a basis of a qubit state of bloch sphere given a general qubit state? There are 3 different basis corresponding to each direction x,y,z where |1> ,|0> is the z basis, |+>, |-> is the x basis and another 2 ket notation for y basis. Given a single state in the x basis...

Homework Statement I'm having trouble worki out the transfer function of the block. Whats confusing me is the input of O2 input of 50. If that wasn't there I know the transfer function would be Oo/Oi=G/1+GH. Homework EquationsThe Attempt at a Solution

An item I want to buy comes backlit blue and I need it to be GREEN. I contacted the seller and asked if I could change the bulb color with a green bulb condom and asked if it was currently a clear led, with a blue cover. THey said yes, but later they then wrote me back saying they made a mistake...

Homework Statement Homework Equations none The Attempt at a Solution I want to find the relationship between B and r. So, i have to change r. Do I just change the coil completely with a new one? I believe that this could greatly affect the set up and I don;t think it is practical. OR is...

Homework Statement So I am given a problem where I am asked to find the time it takes to change the velocity of an asteroid by 1m/s. In a previous section of the problem I was asked to find the force through which the asteroid is being propelled, which I calculated it to be F=1.3x10^4 N, and...

Homework Statement Let D be the triangle with vertices (0,0), (1,0) and (0,1). Evaluate: ∫∫exp((y-x)/(y+x))dxdy for D by making the substitutions u=y-x and v=y+x Homework EquationsThe Attempt at a Solution So first I found an equation for y and x respectively: y=(u+v)/2 and x=(v-u)/2 Then...

Homework Statement Superman pulls on a steel post to trap a supervillian. The post has a cross-sectional area of 30cm^2 and a length of 2m. If Superman applies a force of 6X10^6N by how much is the length of the post increased? A) 2mm B) 7mm C) 1.2cm D) 1.7cm E) 2cm Homework Equations...

Homework Statement If I have the two curves ##\phi (t) = ( \cos t , \sin t ) ## with ## t \in [0, 2\pi]## ##\psi(s) = ( \sin 2s , \cos 2s ) ## with ## s \in [\frac{\pi}{4} , \frac{5 \pi}{4} ] ## My textbook says that they are equivalent because ##\psi(s) = \phi \circ g^{-1}(s) ## where ##...

Homework Statement Consider the real-vector space of polynomials (i.e. real coefficients) ##f(x)## of at most degree ##3##, let's call that space ##X##. And consider the real-vector space of polynomials (i.e. real coefficients) of at most degree ##2##, call that ##Y##. And consider the linear...

<edit: moved to homework. No template in the post.> An ice maker inputs liquid water at 25 degrees C and outputs ice at -5 degrees C. Assume there is 1 kg of water and the volume does not change. Cp liquid 4.18 kJ/kg-K Cp solid 2.11 kJ/kg-K ∆H fusion 334 kJ/kg I need to...

Homework Statement A black and yellow body at room temperature are thrown into a furnace at very high temperature. How will the initial and final brightness of both compare? Homework Equations λT=constant The Attempt at a Solution The rise in the black body's temperature will be higher...

Homework Statement What would be the increment in heat energy radiated when the temperature of a hot body is raised by 5%? Homework Equations P=σεAT^4 The Attempt at a Solution dP/P=4dT/T dT=5 when T is 100 initially. Let's assume P was also 100 initially for convenience, therefore dP should...

Homework Statement A 0.2 kg plastic cart and a 20 kg lead cart can both roll without friction on a horizontal surface. Equal forces are used to push both carts forward for a distance of 1 m, starting from rest. After traveling 1 m, is the momentum of the plastic cart greater than, less than...

In the question given below, can we change the order of integral so that y can be the independent variable and x be the dependent one?The cylinder x^2 + z^2 = 1 is cut by the planes y=0,z=0 and x=y.Find the volume of the region in the first octant.This may look like a homework question but it's...

Hello all It's been a while ,as I read the almost daily news on climate change , some question come up to my mind , dose the ionosphere has any effect on climate change , as we all know now the Earth magnetic field is weakening ,and the temperature is rising ,dose this two variables related to...

Homework Statement A pole stands 75 feet tall. An angle θ is formed when wires of various lengths of ##x## feet are attached from the ground to the top of the pole. Find the rate of change of the angle ##\frac{dθ}{dx}## when a wire of length 90 ft is attached. Homework EquationsThe Attempt at...

Homework Statement A block is acted on by a spring with spring constant k and a weak friction force of constant magnitude f . The block is pulled distance x0 from equilibrium and released. It oscillates many times and eventually comes to rest. Show that the decrease of amplitude is the same...

Why specific heat of solids and liquids doesn't change with change in temperature?

The current degree I'm enrolled in at my junior college is associate in arts. Since I want to go into Computer Science once I transfer should I change my degree to associate in science instead? P.S. I used the degree progress tracker on my student account and from what it tells me I only need...

1. Homework Statement How to determine the change of R of a non-ohmic conductor from different parts of I-V graph? Please see the sketch attached. Homework Equations R=V/I The Attempt at a Solution For the part that passes through the origin, it is obvious that the...

Suppose a spring of spring constant=K and Length=L is split into two parts L1 and L2, with spring constants K1 and K2 respectively. Then,why is it such that the spring force F=K1*L1=K2*L2=K*L? Please give an intuitive explanation of why the spring force doesn't change? I will be thankful for...

This may be a really dumb question and it's been a long day and I can't get my head around this. If I have two values with errors, say 4 ± 0.5 and 6 ± 1.5, the precentage increase from 4 to 6 is easy its 50 %. But how do I deal with the errors? I want to write (50 ± X) % where X represents the...

Hi all, I have two questions about light in Special Relativity. (I'm going to pad these questions out with a few statements about my understanding of length contraction and time dilation, so you can see how I currently think about it and clear up any misconceptions if I've got the basic idea...

Homework Statement This is the problem. A pair of eyeglass frames is made of epoxy plastic. At room temperature (20.0°C), the frames have circular lens holes 2.20 cm in radius. To what temperature must the frames be heated if lenses 2.21 cm in radius are to be inserted in them? The average...

Suppose I had cylindrically-symmetric rotating magnet surrounded by a plasma. I rotate it on its axis at a constant angular velocity, and so the electric field E produced is non-solenoidal and can be described as the negative gradient of some potential V(x,y,z). The electric field is induced...

Hey! :o We consider the surface $S$ of the space $\mathbb{R}^3$ that is defined by the equation $2(x^2+y^2+z^2-xy-xz-yz)+3\sqrt{2}(x-z)=1$. I want to find (using symmetric matrices) an appropriate orthonormal system of coordinates $(x_1, y_1, z_1)$ for which the above equation has the form...

As I understand it, there are many that take an Eternalist view on time. There are the spacetime coordinates and what exists at those coordinates. That to me seems like a static universe. It could conceptually be represented in a static model, if one were to remove a space dimension and replace...

I am trying to add 'pip' in Python/Scripts to path in Win10 but the method available to do this seems to have changed recently. I used to just double click on 'path' in 'system variables' and paste path to pip (or whatever) at the end of a string of similar paths separated by a semicolon. But...

When helium 4 becomes a super fluid does the proper time change, can this be detected?

I am trying to calculate the increase in pressure caused by liquid nitrogen when it changes from liquid to vapor within a closed, constant volume at atmospheric pressure. How can this be done? Do I need to include the heat of vaporization?

Homework Statement A satellite of mass m is in a circular orbit of radius R about a star of mass M. The star ejects 1% of its mass by means of a spherically symmetric wind which removes the mass to a large distance. What are the new nearest and furthest distances of the satellite’s orbit around...

Hello, Let us imagine a rod resting on a frictionless horizontal surface such that the rod is made up of 2 identical molecules. Let these molecules be named A and B from left to right. If we pull A to the left and B to the right with forces of equal magnitude, the rod must remain at equilibrium...

Homework Statement to 1 L solution containing 0.1 mole each of NH3 and NH4Cl, 0.05 moles of NaOH is added. The change in pH will be? (pK for NH3=4.74) The Attempt at a Solution I have the solution and the answer is 0.48. The following was the first step calculated initial pH from henderson's...

In bolometers, incoming radiation warms a strip of material. this material will have a large thermal coefficient of resistance, leading to a (small) resistance change in the material. the inventor, Samuel Pierpoint Langley apparently used this to detect a cow from 1/4 of a mile away using a...

So enthalpy is the heat content of a system at constant pressure. Enthalpy change is equal to the heat absorbed or evolved by the system at constant pressure. If my understanding is correct, a system whose temperature goes up will return back to that starting temperature if pressure is kept...

How can I change the y-axis ticks and labels in Python? I also want to display the grid at each shown label. When I used the following code, I change the ticks and labels, but it also keeps the default y labels. How to remove the default ticks and labels, and create new ones? fig, ax =...

Hello, Let us imagine a solid immersed in a liquid in a container such that the density of the liquid is less than the density of the solid. This means that the solid must sink. Let us study the solid when it reaches the bottom surface and is now at rest. The forces acting on the solid when it...

Hello, I'm currently taking some summer classes at my college and was assigned a project to transport vaccines from one location to another (travel time ~2-5 hours.) We have to keep the vaccine within the range of 35-46 degrees Fahrenheit at all times. My group and I came up with the idea of...

This is a question I was looking at based on Relativity and John Wheeler's one-electron universe theory. https://en.wikipedia.org/wiki/One-electron_universe My question is this. The faster you move towards the speed of light, wouldn't everything in the universe contract to a single particle...

Homework Statement A straight wire of length 0.20m moves at a steady speed of 3.0m/s at right angles to a magnetic filed of flux density 0.10T. Use Faraday's law to determine the e.m.f. induced across the ends of a wire. Homework Equations E= Nd Φ/dt but N=1 so E= dΦ/dt The Attempt at a...

In this super short video of the derivation of the relativistic kinetic energy, , I'm just stuck on one thing. Around 1:00 minute in, the constants of integration change from 0 to pv when the integration changes from dx to dv. Where does the pv come from? Thanks!

I'm reading about the parable of the broken window, which states: I was wondering if this can be related in some way to climate change as a whole. My reasoning is that given that climate change is a consequence of a lack of knowledge about the sum total negative and positive externalities of...

Homework Statement I've uploaded the question in the attached file. Homework Equations R ∝ 1/p R ∝ M/z2 The Attempt at a Solution I don't understand what is in my lecture notes. What equations do I need to attempt this question? Thank you.

I am having difficulty solving an exercise prepared by our professor for hydrodynamics. I am unsure if Laplace pressure is the correct way to calculate the pressure inside. It comes to my mind that I should've used the equation for hydrostatic pressure instead (##P=P_0+\rho gh##). However, the...

Hello guys, I received an admit to grad school for Mechanical Engineering, where my focus was initially Thermo-Fluids . I've also enquired about the Material Science department at the University(in the USA), and they are willing to let me transfer to the Material Science department provided I...

Hi to all! My question is: Does the relative position of the barycenter of the Earth-Moon system change due to mass distribution changes in the system and would this affect the Earth-Moon distance? For example: Could the sea level rise change the Earth-Moon distance? The only formula I found...