Exercise — 400 discussions

Homework Statement Determine if the following set is a vector space under the the given operations. The set V of all pairs of real numbers of the form (1,x) with the operations: (1, y) + (1, y') = (1, y + y') k(1, y) = (1, ky) Homework Equations The Attempt at a Solution...

Homework Statement Determine if the following set is a vector space under the given operations. List all the axioms that fail to hold. The set of all pairs of real numbers of the form (x,y), where x >= 0, with the standard operations on R^2 Homework Equations The Attempt at a...

Hello, I would like to solve this exercise in the best way as possible. I solved using the most trivial way and I am in doubt if are there some better way to solve. Homework Statement Simplify: Homework Equations \left(x + \frac{1}{x} \right)\left(y + \frac{1}{y} \right) +...

One concept in physics that has never set well with me is the way work and energy are defined. According to all the physics sources I've looked at, work is defined as: W = \vec{F} \cdot \vec{d} (for a constant force over a distance) However, intuitively the notion of taking the dot...

Everyone knows college is tough. My professer suggested to me that I should daily do some strenous exercise for at least half an hour. I think he gave that suggestions, so that I could reduce my stress level and after exercise my brain will be fresh so I could study better. I on the other hand...

Homework Statement Hi guys, I don't reach the correct answer to an exercise. I'm following Ashcroft's book. I must find that the reciprocal of the bcc Bravais lattice is a fcc one and the reciprocal of the fcc Bravais lattice is a bcc one. Homework Equations If a_1, a_2 and a_3 are...

Please, can you check the following execution is correct? Problem text I have a plane in affine space in R^4 described by two following equations: \begin{Bmatrix}3x+y-z-q +1=0\\ -x-y+z+2q=0\end{Bmatrix} I have the coords of a point P: (0,1,1,0) Describe the locus of points Q such that...

Hi, I'm working on exercise 9.13 of the "bible" Gravitation. The problem I have is how to derive the following equation: R_x(t)R_z(\psi)R_x(\theta)R_z(\phi) = R_z(\psi-tsin\psi cot\theta)R_x(\theta+tcos\psi)R_z(\phi+tsin\psi/sin\theta) Where R_x(t) denotes an infinitesimal rotation about...

Hello! I'm here again, now with a new exercise! :biggrin: Homework Statement A block of mass m is at rest over this wedge (it's a triangle) of mass M that is at rest over a table. There is no friction. The point P of the block has a height h from the table. Then the block starts to move. What's...

Homework Statement Hello! I'm trying to solve this exercise: A bullet with initial velocity v and mass m pass through a block of mass M in a pendulum of length L and leave the block with velocity v/2. Which value of v will make the pendulum describe a circumference? As you can see, English is...

Hello, I'm given this linear transformation and I'm asked to do the typical calculations (kernel, image, dimensions, etc.) but there's one thing I'm not sure I understand, here's the exercise: f(1,0,0)=(-1,-2,-3) f(0,1,0)=(2,2,2) f(0,0,1)=(0,1,2) a) Is f invertible? b)Find a basis of...

Hey people, could someone solve this problem and explain step by step? It's from a past exame and I really need to know how to do it, tried everything I know (not much tho). Please don't omit steps.Really appreciated! imageshack.us/photo/my-images/403/dvidafrumdelgebra.png/

Homework Statement In the exercise 8.4 from Quarks and Leptons. An Introductory Course in Modern Particle Physics - F.Halzem,A.Martin we can see: if the charge distribution \rho(r) has an exponential form e^{-mr}, then: F(q) \propto (1 - \frac{q^2}{m^2})^{-2} where...

Homework Statement Let x=(x1,x2,x3), Ax:=(x2-x3,x1,x1+x3), Bx:=(x2,2x3,x1) Find: (3B+2A2)x. Homework Equations The Attempt at a Solution Warning: I have no idea what I'm doing! (3B+2A2)x = 3Bx+2A2x 3Bx = (3x2,6x3,3x1) Now to find 2A2x. Considering that an index has a...

Hi, Everyone. I have an electronics I exams tomorrow, and I'm looking for help in solving the following exercise if you don't mind. The exercise tells that this circuit is to be fabricated with a transistor type whose β is in the range of 50-150. It asks to find the value of Rc, so...

"Relativistic Mass" thought exercise with approaching bodies I understand that the concept of 'relativistic mass' is somewhat controversial, but for reasons that are unclear to me. Nevertheless, I humbly pose the following thought exercise/inquiry: For starters, I understand the formula for...

Homework Statement A uniformly charged wire or radius R1=0.02m runs down the axis of a cylinder of inner radius R2=0.06m. The potential difference between the wire and cylinder is 60 volts. Find the electric field at the surface of the wire. Homework Equations Electric flux=Q/\epsilon0...

When reading tips on various websites of how to "study physics" I always see they bring up exercise as being one of the key things to success. But, is it really that integral to one's success? I'm quite skinny and frail, and I've noticed most of my professors and other classmates aren't in shape...

Homework Statement Just click the link, The image is huge, so I did not use IMG tags. http://i.imgur.com/zWNRf.jpg Homework Equations Let's see, The rotational kinetic energy of a body is given as K = \frac{1}{2}Iω^{2} for a point mass, I = mr^{2} for a rigid rod rotating at it's end...

Homework Statement This is an exercise from 'How to Prove it - A Structured Approach' (Exercise 7a, page 54) . So far a a really great book. Homework Equations The DeMorgan, Absorption, Idempotent, Double Negation, Commutative, Associative, Distributive, Tautology, Contradiction...

I need a good book, or in other words a book and it's solution manual if available on line - in classical physics. Some Lagrange, Hamiltonian exercises, with good explanation. Thanks in advance.

Hi all. From Hoffman and Kunze's book Linear Algebra, page 27, exercise 12: What's the most elementary way to solve this? Any hint is appreciated.

As it is right now, I'm fairly certain I have E.I.A. I've setup an appointment with my doctor but the soonest I could get one was 2 weeks from now, so I've been trying to further educate myself on it so I could go in with a little bit better of an idea of what I think I have. At first I...

Hey guys, I've been given a worksheet with a couple of questions concerning radioactivity, half-life etc. It is high school level and for me, it seems like the first year doing physics as our current teacher is the first one who really knows something about the subject. :) So please be patient...

In Cooper's book, I can't think out the solution of the following exercise. Show that each creative set is contained in some simple set. By the way,they are not homework question. I read the book on my own and I am a beginner. Thanks for your hint.

Hi guys, It's been a while since high school, and now I'm faced with a problem I need to solve in a few days (attached). Would someone please help me through that? I would really appreciate support.

Homework Statement I apologize if this is not the right place to put this. If it is not please redirect me for future reference. 11. Consider a uniform thin disk that rolls without slipping on a horizontal plane. A horizontal force is applied to the center of the disk and in a direction...

I'm using the app on my iPod that's for myfitnesspal. Great app to help count calories. Also, I'm doing the Zumba exercise program to help with the weight loss/tone up. Any opinions on all of this??

YBa2Cu3O(7−x)(s) + ([ 7/2]−x)H2(g) → [ 1/2]Y2O3(s) + 2BaO(s) +3Cu(s) + ([ 7/2]−x)H2O(g) 35.937 ± 0.005 mg of solid YBa2Cu3O(7−x) reacts completely, according to the above equation, in a stream of hydrogen gas at 1000°C, leaving 33.242 ± 0.005 mg of solid residue. (For the purpose of this...

Homework Statement Write a Matlab function that takes as input three integers n, a and b, and outputs the number of positive integers less than n that are divisible by a or b. For example, with n = 1000, a = 3 and b = 5, the output should be 466. Homework Equations MATLAB's use of...

Homework Statement Prove ∃x(P(x) → ∀y(P(y))). Homework Equations The Attempt at a Solution ∃x(P(x) → ∀y(P(y))) is equivalent to ∃x(¬P(x) ∨ ∀y(P(y))). This exercise is found in a section on "proofs involving disjunctions." I have tried many different ways to solve this and...

Hello, i have to solve the following problem, i have the result, but i can get the way to arrive to it. This is the problem: There are 2 spheres of copper, separated at 1 meter, each sphere have a weight of 1 Kg initially. The problem want's to know how many electrons i need to transfer from...

Homework Statement Use the fundamental solution or Green function for the diffusion/heat equation in (-\infty, \infty ) to determine the fundamental solution to \frac{\partial u }{ \partial t } =k^2 \frac{\partial ^2 u }{ \partial x ^2 } in the semi-line (0, \infty ) with initial condition...

I'm having problems with what seems like a simple Bernoulli exercise where I can plug in all known variables but not get an answer (using Excel). If I reduce my system down, it would be exactly like a venturi/pipe flow problem except that flow is in the direction of small pipe to large pipe...

Homework Statement Two students on the ground, separated 100m from each other, launch one rocket each vertically. The rocket explode at the same time for an observer, on the ground, that's midway between the rocket explosion. At the exact time the observer sees the rockets exploding a...

I have this question for my physics assignment. Homework Statement Two plane glass plates 10.0 cm long, touching at one end , are separated at the other end by strip of paper 1.5x10^{-3} mm thick. When the plates are illuminated by monochromatic light, the avreage distance between...

Can you help me on this problem please? I tried searching online, but I cannot find the proof: In T_3 space (or regular and T_1 (any one-point set is closed)), show that every prime z-filter is contained in a unique z-ultrafilter. I feel so stupid because I spent lots of time and I cannot...

Hi everybody, I'm having a problem with the following question: A piston-cylinder device originally contains 5 kg of saturated-liquid water at 100 kPa. Determine the heat addition required to bring the fluid to a saturated-vapor state. Using the first law.. i was thinking the following...

How to find value in root finding exercise? I am designing a fountain for a Vegas hotel which sprays water in the shape of a hyperbola onto a screen. The hyperbolas shape is a function of several different variables. I am looking for conditions which will cause the area cast by the bottom and...

Homework Statement Given here is an Operational Amplifier, its feeding Voltages are +-10. A) Calculate Vin to get a Vout of -2V, point out the direction of the current in this case (From a to b or b to a) http://img72.imageshack.us/img72/2550/needheed.jpg The Attempt at a Solution...

Homework Statement In an experiment of Stern-Gerlach, a beam of hydrogen atoms exit an oven with a temperature of 500 K and goes through a 0.5m region in which there's a gradiant of magnetic field of 20 Tm^{-1} whose direction is perpendicular to the beam. Calculate the separation between the...

Homework Statement The \alpha lines of Paschen in the hydrogen spectrum are due to transitions n=4 \to n=3. Identify the allowed 4p \to 3d transitions and determine the change in wavelength for each transition if there's an external B field of 2T.Homework Equations \Delta E=m_l \mu _B B...

Homework Statement A graded steel cylinder AISI 1030 is connected to a wall and loaded with axial forces. http://img542.imageshack.us/img542/3959/fbd1.jpg Given: F = 30 [kN] d1 = 35mm d2 = 20mm Elastic Model: E = 2x105 MPa Safely coeffecient: 2 Yield strength limit: 440...

Hi all, So, I've been trying to get my head straight about a luminiferous aether and have been reading about the experiment of Michelson and Morley. It seems there are many factors of SR that get in the way of this experiment actually producing any plausible results. I assume the whole point of...

Hi, i have tried to solve exercise2.16 in Lee' s book, smooth manifolds: Let X be a top. mfd with the propert that for every open cover O there exist partition of unity subordinate to O. Show X is paracompact. I think there is a trick to construct locally refinement open cover by using...

This is my first topic. I'm sorry for my english: that is not my language. On the planet A, sferically symmetric and with no atmosphere, an astronaut on one pole throws in vertical upwards, a little ball giving to it a certain velocity: this ball reaches the maximum height of 25 cm. The same...

Prove: If x has a right inverse given by a and a left inverse given by b, then a = b.The Attempt at a Solution One thing that bothers me: how can we even talk about a left inverse or a right inverse without establishing that x is in an algebraic structure? I wrote this in my proof but I'm not...

Homework Statement The acceleration of a body is defined as a=-K*u^2 , K is const. When t=o sec V=Vo. Find : a) V(t) b) X(t) c) V(x) . Homework Equations The Attempt at a Solution

Homework Statement is e^x^2 = 4 equivalent to e^x = 2 Homework Equations As above The Attempt at a Solution This is just an exercise, but I'm quite stuck as how to show this is true (or false for that matter). I thought to take the log of both sides and use the log identity to get...

Hello, all. My colleagues and I are currently working on an exercise book for The Feynman Lectures on Physics (FLP). This book will include about 1000 exercises from the original Feynman Lectures course as taught at Caltech, covering pretty much the entire range of topics in all three volumes...