Exercise Definition and 543 Threads

Homework Statement A 2 MeV (kinetic energy) positron collides with an electron at rest. Find the wavelength of the resulting two gamma rays in the center of mass system. use the fact that E^{2} - p^{2}c^{2} = m^{2}c^{4} is invariant between frames of reference for any system)Homework...

Hi guys, i am not sure if its here i should post this but couldn't find a better category. Just wondering, after exercising, we're often thirsty and drinking isotonic drinks is better than drinking normal water, why is that so?

i don't see how this makes any sense at all. http://www.time.com/time/health/article/0,8599,1914857,00.html

I want to know the relationship between the resistive forces of a gyroscopic exercise tool and the revolutions per minute of the rotor.

You are designing a delivery ramp for crates containing exercise equipment. The crates weighing F_1 will move at a speed of v at the top of a ramp that slopes downward at an angle \phi. The ramp exerts a kinetic friction force of F_2 on each crate, and the maximum static friction force also has...

Homework Statement Hi, I have been having huge problems with dealing with these kinds of problems, I would appreciate atleast some guidance in dealing with these sorts of problems, I think the major problem is just how I learned to solve them, I have been looking for resources on the net, but...

I'm a physics student and need to come up with an idea for a relatively simple program for a programming exercise. The scope of the work is 5 ECTS credits which translates to about three weeks full time work. The program should probably include a simple gui so part of the effort goes into...

Hi, Does anyone know how much your temperature increases after exercise? and why the difference?

http://abcnews.go.com/Business/WellnessNews/story?id=7354193&page=1 If there was 1 piece of exercise equipment that Evo would buy, ... hmm.

Ok. Folks, first off this is my first post, and I am looking for some answers to some questions I have. I hope someone has the time to answer them :) First off, I'm no expert in physics. I know a billion times more than any of my friends but believe me that is not saying much. I have never...

Hello, now I'm reading G.Strang's book Linear algebra and its Applications, chapter about Hermitian matrices and complex matrices. In one of the exercises, there's a sentence: [SIZE="3"][FONT="Times New Roman"]"The real part of z=a+\mathrm{i}b is half of z+\overline{z}, and the real part of...

Hi, I have been puzzled by this exercise for some time. I won't repeat it here as the hint refers to other exercises, so I would be copying a whole page of the book. My question is as follows. After having defined the sets S_i and picked a complex number s not belonging to any of the S_i...

Homework Statement http://img528.imageshack.us/img528/3623/47021164uu2.png http://img18.imageshack.us/img18/8634/21260108gr1.png The Attempt at a Solution I have a question about exercise c. The flux Q is the integral, isn't it? So why do they use the word "then"?

Hi all, I was wondering if there was such thing as a heat creating exercise bike. Made for the purpose of creating heat. It's really cold and the power bill is going up and I am wondering if this idea is stupid or has it already been tried. I would buy one. Any thoughts?

Homework Statement Let S be a set of positive real numbers with an infimum c > 0 and let the set T = {\frac{1}{t} : t \in S}. Show that T has a supremum and what is it's value. The attempt at a solution Ok, so the value must be \frac{1}{c}. But I'm unsure how to start proving...

Homework Statement Suppose X and Y are sets. Let P be all pairs (A,f) where A is a subset of X and f is a function from X to Y. Then P is a poset with the relation (A,f)=<(B,g) iff A is a subset of B and f is the restriction of g to A. Show that if C={(Ai,fi)|i in I} is a chain in P, there is...

Homework Statement http://img168.imageshack.us/my.php?image=eightss5.png Homework Equations I have the lecture notes that is 14pages long that covers this particular chapter and the lecture note provided by my professor does not mention anything with switchs in the lecture note...

Homework Statement A cylinder with a frictionless piston is placed horizontally in an atmosphere pressure 1 * 105 N/m2. A gas in the cylinder is initially at a temperature of 300K with a volume of 6.0 * 10-3 m3. Then the gas is heated slowly to 400K. How much work is done by the gas in the...

Can anyone provide a pointer to the exercise of higgs breaking SU(3)xSU(2)xU(1) down to SU(2)? I expect it to be solved somewhere in the web...

Well I thought it'd be nice to do a little thought exercise. Earlier today I was thinking about how much knowledge & wisdom we've acquired over the years, and was wondering what would happen if something truly disastrous was to happen to the planet... Now I'm going to set up a situation and...

Hey, I'm know that PF is not allowed to give medical advice, I do plan to see my doctor next week. Just want to know what you think about this question which is very general anyway. I am quite fit and run and exercise regularly but i also have excercise induced asthma. It is very mild and...

http://en.wikipedia.org/wiki/Stretching#Possible_Benefits More lifestyle optimization! For the past year, I have basically completely stopped stretching before I run (I run about 5 miles a day). And the reason was basically that Wikipedia article which says that I have not had any major...

In another website (http://www.redhotpawn.com/board/showthread.php?threadid=90807" ) forum the following problem was posted: A man with a hat shows you 3 cards, one completely gold, one completely silver, and one gold on one side and silver on the other. He puts them in his hat, and picks one...

Is anyone else having problems with this? Post some ideas... please?!

I'm referring to question #26 in chapter 3 of Pugh's Real Mathematical Analysis. For those without the book, here's the question: Let X be a set with a transitive relation # (Note: #is just an abstract relation). It satisfies the condition that for all x1,x2,x3 in X, we have x1 # x1 and if x1...

[SOLVED] Proof Thery Exercise Homework Statement Prove the following statement, where m and n are integers: If x = 5m + 6 and y = 5n + 6, then xy = 5k + 6 for some integer k. Homework Equations The Attempt at a Solution X = 5 m + 6, Y = 5 n + 6 X * Y = (5 m + 6) * (5 n +...

Homework Statement In a compact cicrcualr coil "A" (radius R= 25cm),formed by N=150 loops of wire, flows I=10A current. There's another compact circular coil "B" over "A"(radius r= 1.5 cm, loops n= 30) coaxial with "A" distant X ,in which i= 4A flows . in the same direction of "I" (look...

Hi. I'm a math instructor and this problem is given to 1. year economics students. 1. The problem statement In an episode of the TV show "All in the Family", Mike claimed that he could identify different brands of cola by taste alone. He was challenged and presented with three glasses, one...

[SOLVED] Munkres Exercise 22.12 Homework Statement Please stop reading unless you have Munkres topology textbook. Why does Munkres use 3 \delta instead of \delta in part b? I get that replacing the 3 \delta by \delta works fine. Homework Equations The Attempt at a Solution

[SOLVED] N+pi-&gt;N+pi exercise in QFT The due date of this exercise was several weeks ago, but I'm still struggling with this. Since some of the QFT exercises are kind of exercises, that are probably the same all over the world, I assumed there could be a non-zero probability that somebody...

Homework Statement An aluminum clock pendulum having a period of 1.00 s keeps perfect time at 20 degrees celcius. (A) When placed in a room at a temperature of -5.0 Celcius, will it gain or lose time? (B)How much time will it gain or lose every hour. Homework Equations I am pretty...

Does anyone know what happens to the internal and external body temperature during and after exercise? I think that internal temperature increases during exercise and then continues to increase..Im not sure..

Homework Statement Let a>b>0 and let n \in \mathbb{N} satisfy n \geq 2. Prove that a^{1/n} - b^{1/n} < (a-b)^{1/n}. [Hint: Show that f(x):= x^{1/n}-(x-1)^{1/n} is decreasing for x\geq 1, and evaluate f at 1 and a/b.] Homework Equations I assume, since this exercise is at the end of...

1. The problem statement I need to prove that if two metrics are related by an overall conformal transformation of the form \overline{g}_{ab}=e^{a(x)}g_{ab} and if k^{a} is a killing vector for the metric g_{ab} then k^{a} is a conformal killing vector for the metric \overline{g}_{ab}Homework...

This is a multi part question so I'll just ask one part. I never understood where the equation for the Fermi Walker Transport came from and I'd really like to understand this because I think it would be really good for pedagogical value and for better understanding parallel transport, maybe...

Whenever I read a corollary, even a lemma, I try to prove it myself first before reading the textbook's proof. This is because I usually find the level of difficulty of the proof comparable to the exercises in the textbook, and thus the textbook's proof is its (correct) solution (which is a...

Homework Statement I can relate tau and X0 by: \tau = \frac{X^0}{2 \sqrt{2} \alpha' p^+ } Why does that mean the angular frequency is \frac{1}{2 \sqrt{2} \alpha' p^+ } ? Homework Equations The Attempt at a Solution

Homework Statement Apparently the answer is sqrt(2 alpha') *4a. But doesn't equation 9.10 imply that the 4a should just be a 1? Homework Equations The Attempt at a Solution

Homework Statement Two forces, F1 and F2, act on the 7.00-kg block shown in the drawing. The magnitudes of the forces are F1=65.9 N and F2=22.7 N. Take the positive direction to be to the right. Find the horizontal acceleration of the block, including sign...

Not wanting to steal the Bow flex thread, I thought it might be fun to post your favorite and and or "most ridiculous exercise device". Late night infomercials have and endless supply of nearly worthless devices...and a few good ones. Gimme a break, is this one for real? How about...

This is an exercise from a book from Serre called Trees. Given the group G = < a, b, c | bab−1 = a2, cbc−1 = b2, aca−1 = c2 > I have to prove G = 1. I don't have a clue. Of course G' = G (commutator subgroup equals the group itself) but I don't know what to deduce from that. Another...

Hello! I'm having a bit of a difficulty trying to solve this exercise mostly because of the resistors. So,when short circuiting the voltage source we have the 20ohm in parallel with 40 ohm right?But what about the other resistors are they in parallel or in series with the result 20//40?The...

Consider a floating point binary notation with 16 bits. From left to right, it consists of 1bit for the sign (0= "+"), e bits for the exponent represented in Excess~2^{e-1} and the remaining bits for the decimal part of the mantissa, normalized between 1 and 2 (1 \leq m <2). a) Calculate the...

Homework Statement Could someone get me started with Exercise 2.5.1 in Shankar's Principles of Quantum Mechanics? Does this forum support TeX or LaTeX? Homework Equations The Attempt at a Solution

When a person consumes less than 1000-1200 for a long period of time, their body inturn goes to starvation mode right? And your metabolic rate slows down? Then, by exercising your metablism will increase. If you lower your intake but increase the amount of exercise (or even taken to the extreme...

Please help with the following exercise: Given 2 resistors in series R1=10 ohms, R2= 30 ohms, determine the current flowing through the resistors and the voltage across each resistor, if the potential difference across the wire is V=12V. This is how I solved it: The total resistance Req=...

Please help with the following exercise: How much should the electrical resistance of a light bulb be in order to consume a power of 60W if a voltage of 220V is applied? This is how I solved it: Power= Voltage^2 / Resistance 60W = 220V^2 / R R = 807 ohms Is it correct? Thank you.

Please help with the following exercise: Two conductor spheres with radius R and 2R are at a great distance one from the other. We put a charge of Q=+1.7C on the smaller sphere, and then we put them in contact with a conductor thread. Determine what charge the spheres will have at...

Hi, I need help with the following exercise: Homework Statement We have a square circuit, with 4 capacitors, 1 on each side of the square, all with the same capacitance C. Calculate the total capacitance of the system of capacitors between the two diagonally opposite corners of the square, A...

It is a nice question. It has a few different kinds of proofes. So who is smart here? :wink: