Couple Definition and 445 Threads

I am having some trouble with a couple of physics h/w problems and would appreciate any help you can give me.. Julie pulls a 61.5 N bag a distance of 278 m at a constant velocity. The force she exerts is 48.4 N at an angle of 66.8 degrees above the horizontal. I found the work julie does on...

thanks in advance for any help

I have no idea how to do this first one 1. Youre coasting with a friend on a sled, going a constant velocity, having a momentum of +120kg m/s when suddenly your friend bails off the sled. Assuming there are no net external forces acting on the system which of the following gives a correct...

I've got a couple of BVP's I'm working on that are giving me some problems. First, I'm asked to solve the 1-D Heat Equation: k \frac{\partial^2 u}{\partial x^2} = \frac{\partial u}{\partial t} in a thin rod of length L subject to the following: BC1) u(0, t) = 0 BC2) u(L, t) = 0 IC) 2...

Please find the attachment below. Thanks

Please find the attachment below. Thanks

I have been learning about moment couples and all of their greatness...but even after seeing and verifying myself the mathematical proof I just can't bring myself to fathom the fact that a moment couple acts as a 'free vector.' How can every single point on an object feel the same moment at...

Please confirm my answers 1) definite integral 0 to 1 [1/1+x^2 + 9e^x - 1/sqrt(x)] = tan^-1(x) + 9e^x - 2x^1/2 I know that to evaluate it I just plug in b for x - a for x 2) indefinte integral sin(3t)cos(3t) = 1/3 (-cos(3t)sin(3t))dt

when a couple acts on an object it will tend to rotate it and it will not tend to translate it But the sentence "tend to rotate" but tend to rotate about which point or axis?

I'm having trouble with these two questions. Problem 1: Prove that the multiplicative monoid N of natural numbers 1, 2,... is a free commutative monoid. Problem 2: Is the multiplicative monoid N isomorphic to the additive monoid N_0 x N_0 x ...x N_0 (n times), for any n = 1, 2,...? Prove...

help needed on a couple questions - electric fields anyone able to lend a hand? 1. How many excess electrons must be added to an isolated spherical conductor of diameer 30.0 cm to produce an electric field of 1155 N/C just outside the surface? permittivity of free space and charge on an...

there's a couple of problems that i have to give in at the end of this lunctime that i just can't work out how to approach or what formulas to use: 1. A 70g tennis ball falls 2 meters and bounces back up to a height of 1.9 meters (a)How much kinetic energy does the tennis ball have...

a) if f and g are continuous on [a,b] then: int [f(x)g(x) dx] = int [f(x) dx] * int [g(x) dx] i said false. b) if f is continuous on [a,b] then int [xf(x) dx] = x int [f(x) dx] again i said false (x isn't constant)

I am sorry if this has been posted before. I just stumbled over this link and it got me drooling:-p http://ads.harvard.edu/books/ Does anyone know if the fundamentals of stellar astrophysics by Collins is a good book?

Why don't elctrons just go and stick to the protons in the nucleus as they are opposite charged particles, why do they keep orbiting them. Another question related to this. Why don't planets just go and crash the sun due to gravity, why do they orbit around it,Who told them or set them in...

While studying for my final exam in physics I have come across some problems that I need resolved. 1) Suppose a the energy required to bring an electron in the ground state of an atom to the second energy level is X J and the energy to bring it to the third is Y J. What happens to a photon...

http://www.foxnews.com/story/0,2933,197952,00.html these people suck...

1. A ship with a long anchor chain is anchored in 11 fathoms of water. The anchor chain is being wound in at a rate of 10 fathoms/minute, causing the ship to move toward the spot directly above the anchor resting on the seabed. The hawsehole ( the point of contact between ship and chain) is...

Hey folks, new guy here! I have a couple of, what I believe to be, pretty elementary physics questions. I hope you can help me adjust my formulas and help me figure this out! I have this formula for calculating how long it takes an object to fall a certain distance: Time(squared) = (2 x...

Hi everyone. I have this problem and I don't even know how to start it! If you are familiar with my previous posts, you know that I usually have most of a problem completed before posting here with my difficulties, however, I cannot even start this one! I don't think there is enough...

Think and Explain 1. Why is it important that the resistance of an extension cord be small when it is used to power an electric heater? 2. Will the current on a light bulb connected to 220V be more or less than when the same light bulb is connected to 110V? How much? 3. In 60- Hz...

Are these the correct answers for the following questions? 1 Solve the Bernoulli equation. a) x\frac{dy}{dx}+67=3xy^\frac{4}{3} What I got: \frac{1}{y^\frac{1}{3}}=x+cx^2 b) x^2y'+2xy=5y^4 What I got: 2y^(-3)=\frac{30}{13}\frac{1}{x}+cx^12 2 Solve each differential...

1. A woman at an airport is towing her 29.0 kg suitcase at constant speed by pulling on the strap at an angle above the horizontal. She pulls on the strap with a 40.0 N force, and the friction force on the suitcase is 12.0 N. (a) What angle does the strap make with the horizontal? (b) What...

the first one says: Prove that: a) |sin z | \geq |sin x| b) |cos z | \geq |cos x| Where I guess z = x+iy... What I have done: Well I am pretty stumped on this one, I have though about expanding sin z into (sin x) (cosh y) + (i cos x) (sinh y) . I don't think that helps me prove...

Hey everyone, I've been having a little trouble with a few HW questions. If you guys could point me in the direction (ie- help me find the method to solve) I would really appreciate it. The q's are: 1. The definite integral from 3 to 8 of- x^4(ln3x)dx For this one I am not sure wether I...

I am completely stuck on a couple of questions and would like a bit of help on these. First one. This I have no idea where to even start and I can't find anything on it in my text either. So maybe a formula or point me in the right direction would help.:biggrin: Calculate the fraction of...

can you please help me find a good article on all that weird stuff in modern physics? the article can be specific or general ... it doesn't really matter as long as it pertains to modern physics

Ok so I recently took a sceience test, and it was a disaster, but he's giving us the chance to retake it. The first time through, the only thing that saved my grade was my "creative" answers (my definition for farad was: "Farad Hazim was the first Arabian telemarketer to eat his own head in...

I'm having many a woes with angular accelaration in my DE Physics class. Could you guys explain to me how to do these 3 problems. (If I can get one of them by logical deduction from the other problems don't go out of your way.) Thanks. A merry-go-round accelerating uniformly from rest...

Hi, I’m having a really difficult time in physics, and I need some help on this homework assignment. Here are the questions and the work I’ve done. I really don’t know how to approach them, and at this point, I’m just kinda throwing equations at them haphazardly… 5. A 175 kg weather...

1. Mass M is sliding down the inclined part of a slide at a speed of 1.93 m/s. The mass stops a distance of S2= 2.1 m along the level part of the slide. The distance S1= 1.22 m and the angle theta= 34.70 deg. Calculate the coefficient of kinetic friction for the mass on the surface. I used...

1.) A cookie jar is moving up a 39.7o incline. At a point 0.56 m from the bottom of the incline (measured along the incline), it has a speed of 1.48 m/s. The coefficient of kinetic friction between the jar and incline is 0.15. (a) How much farther up the incline will the jar move? (b) How...

I have another thread for another problem, but no one seems to be responding about this second problem, so i'll post it here. Need to find the magnitude and direction/space angles of the resultant couple moment of two valve handles being turned, as pictured...

Okay, having some problems figuring out how to start this problem on a moment couple: http://img347.imageshack.us/img347/6939/problem55hb.jpg And the same thing for this one: http://img347.imageshack.us/img347/2488/problem64sx.jpg Any tips on how to start each one? I think I just need...

I have a general question about dipoles. Doesn't the magnitude of the electric field attain its highest values in the vicinity of the midpoint of the distance between the positive and negative point charges? This is interesting, because if you consider only one point charge, then the magnitude...

Thank you. Consider a particle moving in a straight line. Does a Large change in speed always lead to a large acceleration? Explain. For a car traveling at a given speed, there is corresponding stopping distance associated with that speed. The stopping distance is the the distance the...

I tried to write a function that would count all possible combinations that 4 couples could sit at a table assuming no man can sit next to his wife or next to another man. and 1wife and 1 husband sit at fixed positions. my problem doesn't compile and it says i either have too many or too few...

Right now I've only learned 3 equations dealing with constant accleration v_f=v_i+a_s\Delta t s_f=s_i+v_i\Delta t+1/2a_s(\Delta t)^2 v_f^2=v_i^2+2a_s\Delta s Ok first problem: A Porsche challenges a Honda to a 400-m race. Because the Porsche's acceleration of 3.5m/s^2 is...

Hello everyone, I'm stuck on some problems, This is the first homeowrk assignment and I'm pretty lost! I'm going to list the directions and show you what I have done so far, any help would be great! Here is my work to the problems: //http://img175.imageshack.us/img175/4090/4108rz.jpg...

ok this is a new subject and my teacher is just horrible, so any help will be great thanks 1. One cubic centimeter (1.0 cm3) of water has a mass of 1.0 e-3 kg. Determine the mass of 1.0 m3 of water (in kg). -I thought you would take the 1.0 e-3 kg and multiply it by 100 since you are going...

I have a couple math questions that I am a bit rusty with. I know they are probably really easy, but bare with me, as I haven't done problems like these in a while. Here we go: A man makes $75,000. He must pay federal personal income tax of 10% on the first $12,000 of his income, 15% on...

what is this problem searching for? A 25-lb force acting in a vertical plane parallel to the yz plane is applied to the 8-in.-long horizontal handle AB of a socket wrench. Replace the force with an equivalent force-couple system at the origin O of the coordinate system. See attached pic...

Hi, I have a couple general (pretty much abstract) mechanics questions, and I'm not sure I'm going the right way about doing them. Any help would be appreciated. 1)On a flat surface with friction, you have a massless spring with a spring constant (k) attached to a wall on one end, and on the...

A few trig problems that require the same thing or concept. As always I appreciate the help. 1) If Tan A=1/3 and Tan B=1/2 show that Tan(1/3 + 1/2) = 1 (Tan1/2 + Tan1/3) / 1-tan(1/2)tan(1/3) I am a little confused with this because I can't use a calculator and am confused on what...

Good evening scholars! i just had a couple of questions about QNs. ok so the problem says: Give the sets of {n, l, m, s} for the electrons in: a) 4p^2 b) 6s^2 i just want to see if I'm on the right track. here's what i put for the first one (a): n= 4 l= 1 m= -1, 0 s= +/- 1/2...

Physics 2 exam tomorrow. Need help with a couple more problems and I am good! :) 1. a circuit has a 137 mH inductor across AB (the whole curcuit is a square with corners ABCD), a 50 ohm resistor across BC, and a 25 uF capacitor across CD with a 115V @ 60 hz power source between DA. What is...

we recently started integrals over the complex plane, in complex analysis. But, I am confused on the iterpretation of some of it. From what I've heard/understand, there Is no geometrical interpretation of a complex integral. Why is this? Also, why is it 'illegal' to do an indefinate integral...

1. Two builders carry a sheet of drywall up a ramp. Assume that W = 1.70 m, L = 3.20 m, = 18.0°, and that the lead builder carries a weight of 137.0 N (30.8 lb). What is the weight carried by the builder at the rear ? I know torque and all forces add up to zero, as the drywall is not...

Hi to anyone reading this. This is my first thread on this site. I am enthusiastic and very interested in physics. Currently i am trying to understand the universe around me. I have a couple of questions id like to ask and if they could be answered that would be greatly appreciated. Personally...

Why do two objects when dropped on the floor make different sounds? (i.e, coin and piece of wood) What's a system? and please give me an example of it demonstrating Newton's First Law of Motion. How do I calculate the speed of an object that demonstates linear motion?