Homework Definition and 998 Threads

Homework Statement Sheldon moves a box of comic books to stuarts comic book store by attaching a rope to the box and pulling with a force of 90 N at an angle of 30. The box of comic books has a mass of 20 kg and the coefficient of kinetic friction between the bottom of the box and the sidewalk...

Hey there, Back in PF-3 we had the "thanks" button, which we could use to thank whoever solved our HW question. We don't have that feature any longer, which begs the question: What's the protocol for when someone solves our homework question? Should we "like" the post? Should we reply with a...

Homework Statement The first stage of a space vehicle consumed fuel and oxidizer at the rate of 1.60 104 kg/s with an exhaust speed of 3.05 103 m/s. Find the acceleration the vehicle had just as it lifted off the launch pad on the Earth, taking the vehicle's initial mass as 3.00 106 kg...

Homework Statement You are riding in a hot air balloon at an altitude of 167 meters traveling at a horizontal speed of 24 m/s. If you fall out of the basket, how long will it take you to hit the ground? How far will you travel horizontally in this time. What is your total speed when you hit the...

Homework Statement A ball is held by a vertical tether C. The vertical tether C is held be tethers A and B (which are slanted). Tether A has an angle of 30 degrees. Tether B has an angle of 60 degrees. The ball has 150 Newtons. The system is in an equilibrium. What are the Newtons in theaters...

Homework Statement 2. Homework Equations [/B] See question The Attempt at a Solution Ok 1a) is dead simple. But I am struggeling with part b. I plug in all the variables. But cannot seem to get a and b... I do this: (-b)(S_x)(a,b) = E(a,b) and then get -b^2h/2= Ea and ah/2=E I don't...

Homework Statement Hi there! So I'm working on an old homework problem for review so that I actually have the solution, but I'm not sure how to compute a certain part. Here it is: $$\int \int rcos^2(\theta)dr - r^2cos(\theta)\sin(\theta)d\theta$$ Homework Equations The solution involves (what...

I've got this problem with my HW. Would appreciate the help. Thanks. 1. Homework Statement A metal peace with the density of 10,4 g/cm3, has a hole on the inside. The metal weighs 8,2N in air and 7,1N in water. What is the volume of the hole? Homework Equations V = m / ρ m = Fg / g Maybe some...

An infinitely long solid insulating cylinder of radius a = 5.2 cm is positioned with its symmetry axis along the z-axis as shown. The cylinder is uniformly charged with a charge density ρ = 23 μC/m3. Concentric with the cylinder is a cylindrical conducting shell of inner radius b = 14.2 cm, and...

Homework Statement Given the functions Q(v,w) and R(v,w) [/B] K = v(dQ/dv)r and L = v(dQ/dv)w Show that (1/v)K = (1/v)L + (dQ/dw)v (dW/dv)r I have the problem attached if for clarity of the information. Homework Equations I assume everything is given in the problem. The Attempt at...

Homework Statement The height of a helicopter above the ground is given by h = 3.30t3, where h is in meters and t is in seconds. After 1.80 s, the helicopter releases a small mailbag. Assume the upward direction is positive and the downward direction is negative. Already solved for Initial...

(a) State precisely the definition of: a function f is differentiable at a ∈ R. (b) Prove that, if f is differentiable at a, then f is continuous at a. You may assume that f'(a) = lim {f(x)-f(a)/(x-a)} as x approaches a (c) Assume that a function f is differentiable at each x ∈ R and also f(x)...

Hello everyone, I have this physics assignment to do and I would sure appreciate your guy's input. My attempts to answer the questions are below. Could you please let me know if I'm correct or if I'm wrong or missing anything? Thanks a lot in advance! 1. When you drive a car, might you...

Homework Statement (a)The current density across a cylindrical region of radius R varies according to the equation: J=J0(1-r/R), where r is the distance from the axis of the cylinder. The current density is the maximum J0 at the axis r=0 and decreases linearly to zero at the surface r=R...

Homework Statement I have attached the question in image format. Homework Equations The Attempt at a Solution I attached my attempt at solution as images. Kindly have look at them.

I need help in creating a weighted timing controller that uses 4-bit DIP switch (Weight), 1-bit DIP switch (Fast/Slow operation) and etc. The question is shown below. Creating a Weighted Timing Controller: A simple microwave oven has two cooking modes: a "Slow cooking" mode that operates on...

Homework Statement I've gotten to the point where I have ln(e^(-cx) - e^(-cy)) = ln(g) how do i solve this for x ?

Homework Statement Write a recursive function void recurTriangle ( int n, char ch ) which prints out an upside-down triangle. The parameter ch is the character to be used for drawing the triangle, and n is the number of characters on the first row. For example, if n is 7 and ch is ’+’...

Homework Statement Lim ( 5+6x2)/(√(x3)) + 2x2 +1) x->∞ Homework Equations not allowed to use lhopitals rule The Attempt at a Solution first, i divided by x2, which yielded (5/(x2) + 6 + √(x)) / (2 + 1/x2 ) then i assumed that thelim x--> infi of 5/x2 = 0, lim x-->...

Homework Statement 1. Suppose that ##f = 0## at all points of a rectangle ##R## except on a set ##D## of outer content zero, where ##f \geq 0##. If ##f## is bounded, prove that ##f## is integrable on ##R## and ##\int \int f dA = 0##. 2. Now suppose ##f## is an integrable function on a...

I am upgrading and this question i just can not process please help. I will be very greatful. Abigail needs to create a four-digit password to access her voice mail. She can repeat some of the digits, but all four digits cannot be the same. Determine, to the nearest percent, the probability...

I realize that there is significantly less grading to do for professors with online homework. The program does everything for you. However, from a student's perspective I absolutely abhor it. It makes me want to go postal when I have to re-do questions because of round of error (sometimes the...

Homework Statement The problem is as follows: Harvard Bridge, which connects MIT with its fraternities across the Charles River, has a length of 364.4 Smoots plus one ear. The units of one Smoot is based on the length of Oliver Reed Smoot, Jr., class of 1962, who was carried or dragged length...

Homework Statement (Pathria 6.11) Considering the loss of translational energy suffered by the molecules of a gas on reflection from a receding wall, derive, for a quasi-static adiabatic expansion of an ideal nonrelativistic gas, the well-known relation ##PV^{\gamma} = \text{const.}## where...

Homework Statement "A small plastic sphere (with a mass of 2.60 X 10-15 kg) is suspended between two plates, with a potential difference of 265.4 V across the plates. The separation of the plates is 0.500 cm. The upper plate is negative and the lower one is positive. a)What type of...

Homework Statement For the following reactions draw Feynman diagrams, clearly labelling all the quarks, leptons and exchanged particles and stating the type of interaction involved (if more than one interaction could be involved give the most likely): (i) ##\pi^0 \to \gamma + \gamma##...

2. A group of Japanese physicists works on a project where planar lines are in the form of solutions to equations a⋅x+b⋅y+c=0 where a , b , and c are fixed reals satisfying a2+b2≠0 . They need to know formulae for the images of the line a⋅x+b⋅y+c=0 in the following cases: 1. Under the...

Hello I have a steel shaft which is loaded by a pressure force in axis direction. If I want to calculate the maximum force I have to proof if this is a kink according to Euler or not. For steel E295 there is a Lambda_p = 89 In my case I calculated that Lambda is 125 --> Lk/i --> i =...

The best question I can ask at this point is this: is there a way to order things or arrange things of which it is not even possible to use numbers or any form of numerical counting?

TLDR; I'm looking for a good online source for electromechanics material I can pre-learn prior to taking the course at university Hi folks, In the fall I'm starting my last semester of EE, and one of the courses we have to take is Electromechanics. We just found out who the professor is...

A galvanometer of coil resistance 50 Ω deflects full scale for a current of 3.50mA. What series resistance should be used with this galvanometer to construct a voltmeter which deflects full scale for 35.0 V ? r=50 Ω I=3.50mA=0.0035 V=35.0v R=? I= V/R The Attempt at a...

Homework Statement Factorate the expression a(1-b²)(1-c²) + b(1-c²)(1-a²) + c(1-a²)(1-b²) - 4abc Homework Equations Algebric identities The Attempt at a Solution It seems to be an olympic problem, and I can't find the right factors for it. I would really appreciate the help and, if...

is there any other way to find the limit on 58(b). its on page 3 of the link. http://www.math.uga.edu/~clayton/teaching/m115f09/homework/hw2solutions.pdf

Homework Statement How divergence of r (cap)/ |r|^2 is equal to zero? Homework Equations r(cap)= x(cap)+y(cap)+z(cap) |r|^2 as x^2+y^2+z^2 The Attempt at a Solution I tried the problem and end up with with a different solution I took r(cap)= x(cap)+y(cap)+z(cap) |r|^2...

1. The problem. Given that z= 3-4i Show that z^2 = 3-4i Hence or otherwise find the roots of the equation (z+i)^2=3-4i 2. My attempt. The first part of the problem is strait forward z^2= (2-i)(2-i) then expand to get the desired result. Now the second part (z+i)^2=3-4i. Becomes z^2+...

Consider two black holes: the left one has a mass M1= 5x10^30 kg, and the right one has a mass of M2= 9x10^30 kg, and they are a distance d= 3.0x10^6 m apart. A spaceship passing between them is having engine trouble and so the captain has to park the ship somewhere where he won't get sucked...

Why capacitance behaves as shortcircuited in uncharged state and why as open circuited when its fully charged..?? I am reallt doubtful..:confused: i=Cdv/dt...so if we r appyling a dc voltage ..in that case i should be zero.>! thn why short-circuited..??

you may act for an early morning walk. your may work 5m south and 12m east suppose you decided to walk further and go 4m south east and 6m west A.) how far are you from starting point and roughly in what direction? B.)Would you have gotten the same spot had you taken the steps in this...

Hi, Hoping someone will be able to help me out with a electricity homework question that sounds a bit unreasonable to me. Homework Statement Question 8 (Read the section after Q4 first!) The I-V characteristics of a diode and a resistor to be used in a simple circuit with a varaible...

1. Homework Statement :In the diagram,the coefficient of friction between the bigger block and the smaller block is μ1 and the coefficient of friction between the bigger block and the ground is μ2. Calculate the acceleration of the bigger block.(As seen in the diagram,M is the mass of the bigger...

Help me to solve my algebra 1 homework on ages Ramesh's father was 38 years of age when he was born while his mother was 36 years old when his sister four years younger to him was born. Then what is the difference between the ages of his parents? Thanks.

So I originally posted a thread for my optics homework listing every question from a worksheet AND my attempts. Apparently, it's seen as spam so I have tried and am now posting the second question. Homework Statement A concave mirror has a focal length of 40 cm. Determine the object...

Homework Statement A pulley with mass Mp and a radius Rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot. Mass M2 is larger than mass m1. The quantities Tn and g are magnitudes. 1) The magnitude of the acceleration of m1 is ...

Homework Statement A tuned violin, with strings of 31.6 cm each, is placed in front of a speaker. When varying the speakers frequency between 500 and 1500 Hz, it was discovered that a certain string only vibrated at 880 Hz and 1320 Hz. Determine the velocity of the wave in this string...

So I got a warning for just posting questions so I'll do as best as I can to try and put effort lol Homework Statement A Young's interference experiment is performed with monochromatic light. The separation between the slits, d, is .50 mm, and the interference pattern on a screen L =...

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Homework Statement Did I draw the illustration to this problem correctly? https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/t1.0-9/10383553_10152076982180919_2063892221195778510_n.jpg Homework Equations No equations are needed. I just want to know if I drew the illustration...

Homework Statement Left blank Homework Equations Left blank The Attempt at a Solution Well, I am not familiar with the Latex system on this website, just because I am a newbie and I rarely access to this forum. I have a problem (may be simple for you guys) but I still need a...

Homework Statement the signal Vsig has a maximum voltage amplitude +-100mv Vcc = 15V, Rc = 2.2khom, Re= 200ohm, β= 100, Vf = 0.7V, Vce,min = 0.2V, VT = 25mV Assume the Capacitor having negligible impedance for the signal’s frequencies. Homework Equations a. Choose the DC biasing...

Physics homework problem -- design a capacitor Homework Statement An engineer needs to design a capacitor with a capacitance of 1*10-6F using a material with a dielectric constant 260. If the dielectric strength of the material is 8*106 N/C, and the maximum voltage that the capacitor is...