Thanks — 207 discussions

Homework Statement If the cardinality of A is less than or equal to the cardinality of the reals and the cardinality of B is less than or equal to the cardinality of the reals, I need to show that the cardinality of the union of A and B is less than or equal to the cardinality of the reals...

Homework Statement Show matrix is invertible. THanks The matrix A is dened by 1 x1^2 x1^3 x1^4 ...x1^n-1 1 x2^2 x2^3 x2^4 ...x2^n-1 ... ... 1 xn^2 xn^3 xn^4 ...xn^n-1 where x1; x2,... xn are distinct real numbers. Homework Equations The Attempt at a Solution Homework...

Homework Statement Question 1: Vf = Vo + at Find Vo Question 2: P1V1 = P2V2 Find V1 Homework Equations The Attempt at a Solution Vo = at - vf I'm new to taking Physical Science. Could someone help me on understanding how to solve the above problems. I got stuck on...

urgent help needed please, thanks Homework Statement Let A, B and C be any sets inside our universal set U. Decide whether each of the following statements is true or false. Justify your answers by giving a proof or a counterexample as appropriate. a) A⊆B if and only if B'⊆A' b) If...

Questions regarding "Earth life came from Mars" - ? - Thanks Hey guys ans girls, Ok now i am not fully versed in this theory, but the basis is that the life on Earth started from a impact from a piece of mars, that contained organisms, that survived the impact, and started life on earth...

Homework Statement UPS will only accept packages with a length of no more than 108 inches and length plus girth of no more than 165 inches. Assumign that the front face of the package is square, what is the largest volume package that UPS will accept? Assuming the package looks like this...

Homework Statement A searchlight is rotating from a point 'P' positioned 50m from the prison walls. The rotation of the light is represented by the equation d = 50sec2pi(t), where d is the distance in meters, from the light to the wall, and 't' is time in minutes. a) graph the the path...

Ok, here is the problem I have: Figure 2 shows the Moon in its orbit about the Earth, as viewed from space high above the North Pole. Copy the figure into your lab book and for each position A − E shade the appropriate portion of the Moon’s surface as viewed from space, NOT as viewed from...

Homework Statement Here is the problem: GIven the formula below, calculate the expected value of the accerlation, G (in m/s^2). THe mass and radius of Earth are 5.974x10^24 kg and 6.37 x 10^6 m, respectively. Formula to use: g = G Me/r^2 How do I solve for g ? I keep messing up on...

Homework Statement This is for a Astronomy class, and I have to go over a few examples. But I need help understand the proper steps in calculating this. I will give you as much information as you can. I have this formula "For an object dropped from rest, the distance of fall d is...

* Need help with "Finding the point of Intersection" - Thanks Homework Statement Can someone please explain how I would solve this: As in find the pair of the given lines point of intersection. L: x - y = 4 M: x + 2y = 7 Now, Do i have to turn these into slope intercept ? I know...

Astronomy "research" question. Thanks I am doing a study on research ideas for astronomy. This might be hard to explain what I am asking for, but ill try my best :) Basically, I am asking you all for ideas that a graduate or any student can research. Mainly things that have yet to be...

Homework Statement Determine an equation of a line through -3,5 and 1, -3 so... What i got is y - 5 = -2(x-(-3) ) So that turns into y - 5 = -2x + 3 correct? now i am suppose to simplify, and the answer is y = -2x -1 how did they get y = -2x -1 from y - 5...

Homework Statement L: 2x - y = 5 M: x + y = 4 So I got: L: y = 2x - 5 M: y = -x + 4 L has a slope of 2 and M has a slope of -1 Homework Equations ****Now it says find the point of intersection on the graph. How do I plug those points on a graph? Any help would be...

**Quick angular measurement question about moon. Thanks! I am suppose to write a calculation on finding angular measurement of the moon. Does the following make sense, and is correct?

Problem solved! Thanks again Thaakisfox! Homework Statement A ball thrown horizontally at 2.2 m/s from the roof of a building lands 36 m from the base of the building. Calculate the height of the building. Vox = 2.2 m/s Xo = 0m Vx = 0 m/s X = 36m Homework Equations y = Vosin ao - (0.5)(g)(t^2)...

Here is the problem that I am having trouble with (It probably is a no brainer, but i am a bit rusty- not a bit actually, a lot!). Here is the question: A student stands at the top of a building to perform a kinematics experiment. He throws a red ball directly upwards with an initial speed...

**Quick question. Point-Slope. Thanks! Homework Statement Ok i get all of it, except that last part. Here ill show you. Point-Slope question. (4, -3), m = -2 so... y + 3 = -2(x - 4) which then becomes y+3 = -2x + 8) Then... subtract 3 from y + 3, and then do it on other...

Homework Statement Determine the slope and y-intercept of the line: 1/2y = x - 1 - Graph the line Homework Equations I know this is a simple one, but I am having troubles with it. Can someone lay out how they got the slope, and then how they got the y-intercept. pointing out the...

how does a ammeter and voltmeter works? advanced thanks.

Hey guys, this is my first post. I posted here a few time a while ago, but forgot my logins :) I am no physics expert, just really enjoy learning about it when I can. Ok, what I need help understanding is the theory that for example if I leave Earth traveling at the speed of light, and I...

Air with temperature of 80 F is forced with a speed of 30 m/s through a copper tube with length of 1 meter and inner diameter of 2 millimeters. The copper tube has a temperature of -50 F. I want the air coming out of the tube to have a temperature of less than 0 F. Is my design enough or does...

An object of mass m1 moving with velocity v1 in three dimensions collides with a second object of mass m2 moving with velocity v2. We are interested in solving for the velocities of the objects after the collision. There are six unknown values f (v1x)f ; (v1y)f ; (v1z)f ; (v2z)f ; (v2y)f ...

Verifying an integrating factor --please check my work , thanks. Homework Statement Verify that 1/y^4 is an integrating factor for (3x^2-y^2)dy/dx - 2xy = 0, and then use it to solve the equation (1/y^4)* (3x^2-y^2)dy/dx = 2xy* (1/y^4) =3x^2 / y^4 dy = 2x/y^3 dx =3x^2 / y dy = 2x...

Homework Statement R dQ/dt + Q/C = 0 ...Q(0) = Q_0 dQ/dt = - Q/RC integrating factor: mu(x) = e^integ(1/RC) mu(x) = e^(t/RC) (e^(t/RC) Q)' = integ 0 e^(t/RC) Q = t + c Q = te^-(t/RC) + ce^-(t/RC) then apply initial conditions of Q(0) = Q_0 Q_0 = c the last part...

Homework Statement determine the gen sol of the DE x^2y'' - 5xy' + 9y = 0 Q/P = A = -5 and R/P = B = 9 then use y = x^r in original DE... y' = rx^(r-1) y'' = (r-1)rx^(r-2) insert into DE x^2 (r-1)rx^{r-2} - 5x(rx^{r-1})+ 9x^r = 0 i am confused as to how to proceed...

Homework Statement solve the DE using power series about x_0 = 0 y'' + xy' + 2y = 0 so, i want a solution in form of y = [sum from n=0 to n=infinity]c_n x^n (i hope this makes sense, i don't know how to get summation symbol) y = [sum from n=0 to n=infinity]c_n x^n y' = [sum from...

Homework Statement A 2.5 kg block of wood is floating in water. What is the magnitude of the buoyant force acting on the block? Homework Equations The Attempt at a Solution m=2.5kg b=mg=2.5*9.81 b= 24.5N Is this right? Thanks in advance for the help!

1-D Perfectly Elastic Collison PLEASE CHECK! THANKS Homework Statement Mass m1 is moving to the right at a velocity of 17.6m/s. Suddenly it strikes a stationary ball. The stationary ball has a mass of .685kg. The collision is perfectly elastic and 1 dimensional. The collision forces m2 to...

The correct answer is (1/y) - (1/xy) but i don't understand why What does the sum of xy not equaling zero imply that we can do to the equation to solve it?

Homework Statement 009 (part 1 of 2) 10.0 points A 33 kg child sits in a swing supported by two chains, each 3.7 m long. If the tension in each chain at the lowest point is 259 N, find the child’s speed at the lowest point. (Neglect the mass of the seat.) Answer in unit m/s. b. Find the...

Homework Statement if given a scenario for example, a spider is hanging down from a thread of spider web on a train, and when the train moves the spider moved 10 dregees how to find the acceleration for the train? pretend X is the weight of the spider if you don't understand...

I don't think I have done it right! Thanks In Advance! Homework Statement Water flows over a 60-m high waterfall at a rate of 2000kg every 5 seconds. What is the potential power output of the water fall? Homework Equations KE = 1/2 mV*2 V = Displacement/time P = E/t...

Homework Statement hey guys i have been undertaking a project on constructing a small scale hydro electricity generation system. I completed my project and was able to generate electricity using a turbine and a genrator, what i need to do now is find theoretical values for the electricity...

newbie needs muchos help!(thanks) right so i am new to the forums and am really glad i found them.any way just doing some revision and have come across this and i am stumped. Q:In a particular type of hardness test a steel hammer is allowed to fall on a material being tested.If the hammer...

Use the table of values of f(x,y) to estimate the values of each of the following partial derivatives. y=4.2 || 2.75262 ||| 0.27222 ||| 0.27107 y=4 ||| 5.74559 ||| 2.84839 ||| 0.64973 y=3.8 || 7.42708 ||| 5.84832 |||...

some help with this differentiation question thanks Question : Find the indicated partial derivative . frss , frst f(r,s,t) = r ln (rs^2t^3) differentiating with respect to r gave s^2t^3 1* ---------- rs^2 t^3 but this is not correct something is...

Homework Statement how can i convert this : - 2 (cos pai / 4 + i sin pai / 4 ) to Cartesian , Polar and Exponential form ? Homework Equations z = ( a + i b) The Attempt at a Solution r= -2 tan inverse = pai/4 / pai/4 ?? Thank you very much for helping me out

Express -2(cos pai/4+i sin pai/4 ) in Cartesian , Polar and Exponential form ? how can i convert this : - 2 (cos pai / 4 + i sin pai / 4 ) to Cartesian , Polar and Exponential form ? Thank you very much

Homework Statement wtihout using a graphing calc, find the rational roots of P(x) = 2x^4-5x^3+5x^2-5x+3 Homework Equations The Attempt at a Solution The answers are 1 and 3/2, because this is a homework question. I don't know how they got that though. If anybody can help me...

Homework Statement 1. Tom Jager swam the 50 m free in 21.81 seconds. a. Calculate Tom's average speed b. If Tom could continue this incredible pace, how long (in minutes) would it take him to swim one mile? c. Tom races Micheal Phelps. If Phelps swims at an average of 2.35 m/s and the...

a) An elevator travels upward at a constant speed. The elevator is hung by a single cable. Friction and air resistance are negligible. ii) Is the tension in the cable greater than, less than, or equal to the weight of the elevator? Explain. iii) The elevator travels...

Homework Statement Find the resultant of three coplanar concurrent forces, f1 north a magnitude of 8 grams, F2 of magnitude 12 grams and acting southwest f3 of magnitude 5 grams and acting southeast Find the resultant in an easterly and northerly direction. known values: F1 = 8 grams...

HELP ME with THESE QUESTIONS P L E A S E ! thanks 6) a ladder on the ground is leaning against a wall. if the ladder is in static equilibrium,where must a friction force act on the ladder? a. at the wall b. at the ground c. both 7) the period of a simple pendulum in a grandfather clock on...

Apologies for making a long posts, I just wanted to lay down the basic idea of what I'm doing at the beginning. I'm working on a home-made Michaelson type Interferometer. I'm trying to make few changes, mainly modulation of the black-body type radiation (Globar). Instead of amplitude...

some hints on the question... please?! thanks! 1. Assume that the region to the right of a certain vertical plane contains a vertical magnetic field of magnitude 1.00 mT, and the field is zero in the region to the left of the plane. An electron, originally traveling perpendicular to the...

hi just wondering how you would solve this problem A 3 kg toy car with a speed of 6 m/s collides head on with a 2kg car traveling in the opposite direction with a speed of 4 m/s. If the cars are locked together after the collision with a speed of 2 m/s, how much kinetic energy is lost?

"We thank J. Distler and R. Percacci for animated discussions which triggered this investigation. Furthermore, we are grateful to J.P. Blaizot, A. Codello, R. Loll, E. Manrique, and M. Reuter for useful conversations..." It's interesting to contemplate the different ways that progress in...

In my algebra/triganometry-based physics class (on electricity and magnetism) and yesterday our professor went over how to convert and AC generator into a DC generator; it got kind of confusing so i tried to read it over in our book but there's only like 3 senteceson it... could anyone help...

(Tanx)^2(Secx)