Check my work — 196 discussions

Homework Statement Homework Equations The Attempt at a Solution 5.1) fg// = mgSin(theta) = 30437.12 N 5.2) Ek = 1/2*m*v^2 = 1/2*(1.2*10^4)*36^2 = 7776000 J 5.3) Wnet = Ek 7776000 = 30437.12*delta x delta x =...

Just need someone to check my work. Couldn't find the problem via Google. $f$(W,X,Y,Z) M (0,1,2,7,12,15) + d(3,13). 1)Find the minimum Product of Sums equation using a K-Map. 2)Draw a schematic of a minimized circuit implementing the logic using NOR gates. 1) My Answer: $$(\bar{w} +...

Homework Statement Two asteroids are traveling side by side, touching each other. They are both spherical and are made of pure iron. What must their diameters be in feet to exert a force of 3 lb's onto each other?Homework Equations V = 4/3*∏*r^3 density of Iron = 7.63*10^3 1 lb = 4.448N 1 foot...

two blocks of unequal mass are connected by a string over a smooth pulley. one mass of mass 2m rests on the incline while the second mass of mass m is hung over a pulley over the incline if the coefficient of friction is μk, what angle of the incline allows the masses to move at a constant...

Homework Statement Homework Equations The Attempt at a Solution Question 1 1.1) 5 m.s 1.2) Acceleration 1.3) 10 m.s^-2 1.4) Displacement equals area under graph = 1/2*b*h = 1/2*2*10 = 10 m 1.5) vf = vi+at 0 = 10 + 10t t = 1's + 2's = 3's 1.6) 1/2*1*10...

This is collisions and momentum problem. for some reason it just seems like a short problem and I am use to doing long problems so I am here to check my work. the questions is A 50g bullet is fired vertically up at a 1.00 kg ballistic pendulum . The bullet strikes the block at 1000 m/s...

Homework Statement For every x in Z and for every natural number n if: x^{2}\equiv1(mod47)\Rightarrow x^{n}\equiv1(mod47)orx^{n}\equiv46(mod47) The Attempt at a Solution Alright I said since 47 is prime and relatively prime with x then by fermat's little theorem we will get...

Can someone check my work for me please? I'm pretty sure i made a mistake with the sign convention but I'm not sure which sources are supposed to be negative. help! Problem: http://imageshack.us/a/img201/339/circuitzz.png My solution: http://imageshack.us/a/img191/8049/circuitz.png...

∫x^2(√(x^3 + 1)) u = x^3 + 1 du = 3x^2dx (1/3)du = x^2dx ∫√(u)*(1/3)du = 2/3(u)^3/2 *(1/3) = 2/9(x^3 + 1)^3/2 Is this the correct answer? Thank you.

Express e^x from 1 to 8 as a Riemann Sum. Please, check my work? :) 1. Express ∫1 to 8 of e^xdx as a limit of a Riemann Sum. (Please ignore the __ behind the n's. The format is not kept without it...) _____n 2. lim Ʃ f(xi)(Δx)dx x→∞ i=1 Δx= (b-a)/n = 8-1/n = 7/n xi= 1 + 7i/n ____n lim Ʃ...

Charged Sphere with a Hole -- Check my work? Homework Statement You have a spherical shell of radius a and charge Q. Your sphere is uniformly charged except for the region where θ<= 1° (which has σ = 0). Imagine that your field point is somewhere on the positive z-axis (so z could be...

Hi everyone, just me doing my regular Thursday Physics homework and looking for someone to check my work. Homework Statement A tuning fork with a frequency of f=528Hz is placed near the top of a tube. The water level is lowered so that the length L slowly increases from an initial value of...

This is the problem: http://oi47.tinypic.com/6qij4o.jpg I set fx, fy, and B equal to zero. 'x' forces: Fx - Bsin(30) = 0 'y' forces: Fy - mg + B(cos(30)) = 0 lower end: -0.5*mg(cos(30)) + 0.4*B = 0 Using the third equation I solved for B, and got -477.4. I then plugged B into the...

I'm developing a realistic sci-fi story in which power for the outer planets is produced from Jupiter's magnetic field. Now from Faraday's law I have V= N * A * (2*∏*RPM/60) B where N is the number of coils, A is the area of each coil, RPM is, well, RPM, and B is the field strength. I've...

A 1,662 kg car goes from 14 m/s to 29 m/s in 19 secs. What is the average force acting upon it? Write your answer to two decimal places. Attempt: [SIZE="1"]Mass = m = 1,662 kg Initial Velocity = Vi = 14 m/s Final Velocity = Vf = 29 m/s Time = t = 19 secs Acceleration = a =...

Homework Statement Given v0= 0 m/s, xo=0 m and t= 10s, use the equation below together to find Xf Homework Equations x=xo+volt+(1/2)at^2 vf^2=vo^2+2a(xf-xi) The Attempt at a Solution vf=at xf-1/2at^2 vf=2axf so then, plug in t=10 and vf=10a xf=50a ... I don't know...

Physics Kinematics Question! :) (Check my work?) Homework Statement A ball is thrown vertically up from a window that is 3.6 meters above the ground. The ball's initial velocity is 2.8 m/s up. What is the ball's velocity when it hits the ground? How long after the first ball should a second...

Homework Statement Let S_n = 1 + (1/2) + (1/3) + (1/4) + ... + (1/n) a) What value of n is required such that S_n > 100? b) Show how one can form a stack of identical blocks (one per row), each 1 ft long, so as to form a "wing" (I don't know what the correct word in English is, but I...

Homework Statement Look at my work in the picture. Homework Equations The Attempt at a Solution I did a different method and I got 3 and 1 and still 1 is the only T that satisfies.

Homework Statement Hey I just need someone to check my work to make sure I did it right, thanks.

Can someone check my work please, thank you. :) Homework Statement A hockey player of mass 85 kg traveling at 15 m/s [N] collides with another hockey player of mass 70 kg at 5.0 m/s [E]. If the two hockey players lock skates during the collision and are held together, find the resultant...

Homework Statement Its a 3x2 multiplying a 2x2. (3 down 2 across, 3x2) I was gone for the day that my teacher explained it to us, and I am not sure how to do it. I tried, but I want to be sure. Homework Equations 5 2 0 -4 _X_ 3 7 1 6 ___ -2 0The Attempt at a Solution The answer I got was...

Homework Statement A beam of electrons with energy 1.20 keV (per electron) is directed towards a solid copper sphere of radius 1.25cm. a) Determine the velocity of the electrons in the beam. b) The beam continues to send electrons into the sphere until it is charged up enough to repel the...

Could someone please check this for me? I attached a rough free body diagram of the whole frame. Any help is appreciated. Homework Statement The member ACF of the frame loaded as shown is connected to member BCD by means of a smooth peg and slot C with force P = 930 N at point D...

Please, check my work. Homework Statement a) Show that sqrt{[1+tan^2x]/[1+cot^2x]}=tanx b) Show that [cosx+sinx]/[cosx-sinx]=1+[2tanx]/[1- tanx] c)Show that cotxcosx+tanxsinx=(cosecx+ secx)(1-sinxcosx) d) Show that cosec^2x-cosecx=cot^2x/[1+sinx] e) Show that sin^3x-cos^3x=...

A piece of rock contains 10^20 atoms of a particular substance. Each atom has an expoentially distributed lifetime with a half-life of one century. How many centurites must pass before there is about a 50% chance that at least one atom remains. What assumptions are you making? answer...

Let K be a standard normal random variable. Find the densities of each of the following random variables: X= |K| Y = K2 I get: fX(x) = √(2/π) e-x2/2 and fY(y) = 1/√(2*π) 1/√y e-y2/2

The problem is: For the baseball diamond in exercise 33, suppose the player is running from first to second at a speed of 28 feet per second. Find the rate at which the distance from home plate is changing when the player is 30 feet from second base. (the picture basically shows a square with 90...

A solid sphere of +20C with radius a=1m. A conducting spherical shell of -30C with radius b=2m and c=3m is concentric with the solid sphere. 1. Find the inner and outer surface charge of the conducting spherical shell. My attempt: I just eyeballed it and said -20C is on the inner shell...

Okay, I have this problem worked out, but I have no clue if my answers are right. Could someone please check my work and give me some confidence or show me where I may have messed up. Homework Statement Two loudspeakers, one of them generates sound with 400 W power the other with 100 W. The...

Rayleigh criterion and circular apertures-- check my work? Homework Statement Think of the pupil of your eye as a circular aperture 5.00 mm in diameter. Assume you are viewing light of wavelength 550 nm, to which your eyes are maximally sensitive. a) What is the minimum angular separation...

Homework Statement Hello everyone, I was wondering if someone could check my work on this problem as I'm not sure it's right. I'm in Calc II right now and we are doing finding volume bounded by curves rotated around an axis. So, here is the problem, y=cos(pix)+1, y=4x^(2)-9, x=0; about...

Sound Intensity-- just need someone to check my work :) Homework Statement While enjoyable, rock concerts can damage people's hearing. In the front row at a rock concert, 5m from the speaker system, the sound intensity is 145 dB. How far back would you have to sit for the sound intensity...

Homework Statement Hi. I only have one more submission left in my homework. Can someone please check this problem real quick for me? DIRECTIONS: Write the formula for each of the following compounds. (Type your answer using the format Al(HSO4)3 for Al(HSO4)3.) PROBLEM: Ammonium Acetate MY...

Homework Statement Okay, I think these are simple, but just so I know that I am on the right track, can you double check my work? My questions and answers are in bold. Factor these completely: 1. 2e^3x - 5xe^3x 2. 4lnx -3ylnx 3. The Attempt at a Solution 1. I took out the...

Homework Statement I'm looking for the maximum power transferred to resistor R. I know how to approach the problem, but not getting the right answer and was wondering if someone could just look over my work. http://img854.imageshack.us/img854/1412/screenshot20110604at115.png Homework...

Homework Statement Prove that: \frac{d}{dx} \frac{tan(x)}{sec^2(x)} = cos(2x) Homework Equations The Attempt at a Solution \frac{d}{dx} \frac{tan(x)}{sec^2(x)} = cos(2x) \frac{d}{dx} \frac{tan(x)}{sec^2(x)} = \frac{sec^2(x)(sec^2(x))-(tan(x)(2sec^2(x)tan^2(x)))}{(sec^2(x))^2}=...

Homework Statement using mathematical induction, show that d^n/dx^n(lnx)= (-1)^(n-1)*((n-1)!/x^n) Homework Equations The Attempt at a Solution basis step: for n=1 we get d/dx(lnx)=(-1)^0*((0)!/x^1) which gives d/dx(lnx)=1/x inductive step: assuming it holds for all n...

Homework Statement An electron is accelerated horizontally from rest in a television picture tube by a potential difference of 10,000 V. It then passes between two horizontal plates 5.0 cm long and 1.0 cm apart which have a potential difference of 200 V. At what angle θ will the electron be...

Homework Statement A 50g ice cube has no friction. It compresses a string with the constant 25 N*m a total of 10 cm. Find the max height reached by the ice cube before it starts sliding back down the slope, after it is released from the spring. Known: m = 50g (.05kg) k = 25 Nm x =...

Homework Statement You want to heat 1 L of water by 10 ºC, and so you heat it with a mechanical egg beater that is powered by a 1 kg mass on a rope over a pulley. How far does the mass have to descend to supply enough work for heating the water? Homework Equations |work| = mg(x_f - x_0)...

Homework Statement I posted an inequality proof question a little while ago and got some really great feedback. Here's a couple more that are similar to it that I've been working on. I'm still uncertain as to what makes an acceptable proof and what doesn't, so please let me know if I'm on the...

Homework Statement Prove that if a,b > 1, then a+b < 1+ab The Attempt at a Solution Just want to know if this makes sense: first let a+b < 1+ab become 1<(1+ab)/(a+b) ==> 0<(1+ab-(a+b))/(a+b). Factoring the numerator: 0<(1-a+ab-b)/(a+b) ==> 0<(1-b)+a(b-1)/(a+b) So the next...

Homework Statement a telescope has a diameter of 8m. A double star 6000 light years away is viewed. what must be the min distance apart (in ly) of the two stars for their images to be distinguished if light of wavelength 500nm is used? Homework Equations theta = 1.22 (lamda/D) D =...

Homework Statement X and Y have uniform joint density function: f(x,y)= d (constant) for 0<x<1 and 0<y<1-x 1. find d 2. find p(y<x) 3. find cov (x,y)The Attempt at a Solution 1. For this I first graphed x=1 and y=1 and created a square since x can go from 0 to a maximum of 1 and y also. I...

Homework Statement Explain why the series (1+1)/(1+2) + (1+2)/(1+4) + ... + (1+n)/(1+2n) + ... is divergent. Homework Equations For a series to ∑un to be convergent, it is necessary that lim n-->∞ un = 0. The Attempt at a Solution As you may have guessed, I'm going to show...

[PLAIN]http://img178.imageshack.us/img178/4781/345b.jpg So I said v=v0-gt, and at the highest point, v=0, so t=v0/g. I also said uy=u0sinx-gt, and ux=u0cosx. So at t=v0/g, both balls have to be at their highest pint, and when uy=0, t=u0sinx/g...so equating the two times, I find...

Homework Statement [SIZE="4"][SIZE="4"]state the order and linearity of the diff eq (d^2u/dr^2)+(du/dr)+(u)=cos(r+u) 1)the order is the second order. since the highest derivative is 2 2) the term cos(r+u) is not linear therefore this equation is not linear. is my reasoning for 2) right...

I just want someone to check my work this is the problem (3x^2 − y)dx + (y − x)dy = 0 I'm going to use the exact equation method to solve it because it seems like the most practical method for the case...I was thinking substitution but the power is not the same for the highest one. M=3x^2 − y...

Homework Statement Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified line. Sketch the region, the solid, and a typical disk or washer. Homework Equations The Attempt at a Solution Sometimes, I struggled with drawing a...