Calculations Definition and 982 Threads

Homework Statement An object is magnified, by a factor; of 5, in a concave mirror. The mirror has a focal length of 20cm. Calculate ALL possible positions of the object. Homework Equations M=Hi/Ho=Di/Do M=V/U 1/F=1/V+1/U The Attempt at a Solution 1/20=1/V + 1/U -1U=20V/V U=-20...

Hi Homework Statement I have been on some statistics and I am not sure that I am on the right track Given two meassurement zones of radioactive vast: \left(\begin{array}{cc} zone 1 & zone 2 \\ 55 & 55 \\ 44 & 24 \\ 47 & 57 \\ 61 & 37 \\ 15 & 51 \\ 36 & 33 \\ 29 & 39 \\ 69 & 11 \\ 8 & 42 \\...

Dear all I need to fix motor capacity for general mechanical components drive apllications These type of calculation sites if available pl send me the details I cannot find that ones Any reference books pl.forward me (I referred shigley.general mechanical design books but i can't...

I have trouble figuring out how my textbook came up with the totals and am looking for step by step help. Here is what the text shows. Z = R + j0 = R = 56 Ohm (in rectangular form [XL = 0]) Z = R < 0 degrees = 56 < 0 degrees Ohm (in polar form) Z = 0 + jXL = j100 Ohm (in rectangular form...

HI all, I am interested in designing a tapered bearing. Can anyone please let me know the parameters to be considered in order to design. I have been given a load acting on the sleeve, and the arae available to fit the bearing. If any useful site which talks about bearing and its...

Hi- We're thinking of purchasing Gaussian 03 for electronic structure calculations. I think the basic license only allows for it to be run on a single processor. Can anyone recommend a decent desktop <1500 dollars that will do a decent job at running electronic-structure? I suspect that...

"Back of envelope calculations" for thurst, specific impulse, etc. I am working on a project that is really out of my realm of experience, so if you could give me some basics, that would be much appreciated. How do you determine the amount of thrust, power, etc. needed to travel a distance of...

Homework Statement *How many moles of LiH are required to make 1 mole of LiAlH4? * 6 moles of LiH will produce how many moles of LiAlH4? Can someone help me get started on these?

Would anyone help me understand how did the ancient Greeks managed to calculate the earth’s circumference using knowledge of the angle of elevation of the Sun. I wonder if they had any means of magnification such as lens. They did make some pretty accurate conclusions for the limited technology...

So I'm in an intro quantum physics course, and while I'm sure this is a really simple problem, I'm just not getting the math to work out here. Say you excite the atoms of some gas such that they emit light at a wavelength of 5500 angstroms as they fall back to the ground state. Now if the...

"Quick Calculations" by Shi Fengshou in English? I'm looking for an English manual to "Shi Fengshou Rapid Calculations." Apparently the guy wrote a book in Chinese sometime between 1970 and 1980 called "Quick Calculations." However, I haven't been able to find an English translation of it. I...

Two identical, oppositely-charged, conducting plates of area 2.50cm² are separated by a dielectric 1.80 mm thick, with a dielectric constant of 3.60. The resultant electric field in the dielectric is 1.2*10^6 V/m. a)Compute the charge per unit area on the conducting plate. b)Compute the...

Homework Statement Lab: rub each of a set of hard materials against a set of soft materials. Hold the hard materials near a suspended, negatively charged comb (wool rubbed) to determine the charge polarity and strength on the hard item. Create a list of the hard and soft items used in order...

Homework Statement The given data is the perigee altitude r_p, the apogee altitude r_a and the period T. Mission: find the altitude 30 min after perigee passage. Homework Equations Semi-major axis a is calculated. Kepler's equation gives a relation for the eccentric anomaly E: E -...

I have been working on experimental heterogeneous catalysis for a couple of years, specifically with metal oxides. I would like to learn computational modeling on heterogeneous catalysis (e.g hydrogen abstraction on acetone). I actually have no background on computaional calculations. What...

I just want to make sure my logic is correct. Hot coffee in a vacuum flask (thermos) is an example of what type of sytem? Choices: Closed Open Isolated I thought it was closed system because the coffee is not interacting with the surroundings. But one of my classmates said he...

I'm a 3D artist and I'm making an animation that involves a free falling object. I know that, in a vacuum at least, an object will fall 32 feet during the first second; during the second second it'll fall 64 feet -- a total of 96 feet after only two seconds of free falling. The problem is that...

Homework Statement My results are coming out funny and I was wondering if I was doing something wrong. I have to find acceleration due to gravity. one of my values ... m2 (decending mass) = 60g m1(ascending mass)= 50g distance traveled= 95.3cm or .953m time traveled average=...

Homework Statement http://www.tunerspec.ca/school/3dvector.jpg Homework Equations c^{2} = a^{2} + b^{2} - 2ab \times cos \alpha \frac{sin a}{a} = \frac{sin b}{b} The Attempt at a Solution I really don't know where to get started... I don't want someone to just do it for me - just...

Homework Statement A rocket on its launch pad has a mass of 20,000kg. The engine fires at t=0s and produces a constant force of 500,000 N straight up. The engines fire for 1 minute during which the entire 10,000kg of fuel on poard is consumed and expelled from the rocket at a constant rate...

Can a hollow cylinder of known radius, height and charge be treated as a line of charge if one is trying to find the E-field at an arbitrary perpendicular distance from the center of the flat surface?

Hi all, I have a problem with respect to axial strain.As far as I know the axial strain is calculated by using the formula given below. Strain=(L-Lo)/Lo where Lo : Orginal length and L : current length. However, another formula is written in one of the program manuals I have been...

[SOLVED] Power plant Hi! Here i have a problem : A power plant generates 400 MW of electric power.It has an effieciency of 40%. a) At what rate does it dissipate heat? b)If the waste heat is carried away by a river, and the temperature rise of the river must not exceed 3°C, what flow rate is...

Homework Statement I have a physics project in which I need to find a relationship between the distances from each side of the throwing arm of a trebuchet and the actual throwing distances. Let's call the distance from the counter-weight side of the throwing arm to the axle variable 'A'...

Homework Statement A point source of sound emits energy equally in all directions at a constant rate and a person 8m from the source listens. After a while, the intensity of the source is halved. If the person wishes the sound to be seem as loud as before, how far should he be now...

This is an actual real-life problem. There is a machine that winds film at my work. I need to determine the torque required (T_2) and force needed (N) for the conditions showed in my diagram when all variables except F_T2 are known. Roll #2 begins with no film and ends as a large roll with...

I'm not sure if this is the right forum for this topic, so apologies if I got it wrong. I've been reading the Feynman Lectures on Physics. In it, Feynman states that though Quantum Electrodynamics is highly successful, it is still extremely difficult to evaluate the equations to obtain a...

Dear experts, I'm trying to get an equation for tilt angle into a MPU. This is no problem if you can find the equation. The ADXL103 data sheet is indeed mysterious in that it is about a chip that measures acceleration. and yet gives no formula for the relation between...

Hello people...could u help me pls...coz i am rly stuck in these thing like calculations...i know all right answers but i am not too sure how to get them...please if somebody of us has a few minutes could u help me with that? Thank you very much. Azides are compounds of nitrogen , used...

Hello All, I'm doing some fun at home experiments with my 1:6 scale RC car and I wanted do some camparisons with its full scale counter part. Mainly how jumping the two off a ramp (Duke's of Hazzard style). I wanted to know if you can help me with confirming some of my scaling...

What is the benefit of using unit vectors rather than not using them?? I am not seeing the point of them? It seems to me that you can do the same calcs without adding the ihat and jhat. Can someone explain exacly how and why unit vectors make vector calcs easier, or why we need them. Thanks...

I am in the middle of physics debate with someone who has some rather, shall we say, unconventional views regarding classic mechanical physics. It started when he posted that he feels 9/11 was a conspiracy because a section of a building falling does not increase the "load" (as he called it) on...

1. A nonconducting sphere with center C and radius a has a spherically symmetric electric charge density. The total charge of the object is Q > 0. a. Determine the magnitude and direction of the electric field at point P, which is a distance R > a to the right of the sphere's...

I mainly am having trouble accurately calculating the force on members in a truss. The reason being is sort of common, my teacher skimmed through the lecture on these calculations, and left the entire class in a fog. I've made my best attempts at researching on the Internet, but so far no real...

Is there any practical reason for calculating simultaneity of distant events? Two events either are causally connected or not, and there is nothing relative about this. If a cause-effect link doesn't exist, does it matter if the events are calculated to be simultaneous from a certain point of...

Hi there, I have used an orifice for my project to measure the pressure difference and hence the mass flow rate of air going through a pipe of 26 mm diameter. i kept changing the flow from max to min and ended up with values of pressure diference. The questions here is how to convert thses...

My problem (trying to help an ay last keen son)-a lever 5m long, a weight of 300kg, a force of 100kg. The question says describe? I am trying to work out the distance from the end of lever to fulcrum or in other words where the fulcrum should lie. tried formula which has gone to...

Do many chemists or technicians in the chemical businesses find much use for equilibrium calculations of weak acids or weak bases? In practice, laboratory people can make practical measurements, practical preparations, titrate to a certain pH endpoint, even use a pH indicator material, and can...

ok i keep reading that ideally they (neutralisation enthalpies) are meant to be around 58KJ here is my problem: im reacting 50cm3 of NaOH with 25cm3 of HCl the HCl is 1 mole NaOH is also 1 mole. my moles calculation is: (1x25)/1000 which gives me 0.025 the i do : ((mass x...

Hi all I've been calculating heat convection off a horizontal heated plate to still cool air around it. Since the plate has a size of 50m2 the GrPr number is turbulent i there's no equation in my book to calculate heat transfer by convection for GrPr > 10^11, so i used the equation of GrPr at...

I have a question about applying the rules of significant figures to calculations. Should one apply the rules to everyday calculations? I don't know if it will benefit me in the long run to count the number of sig/decimal places in numbers in the simplest calculations. If I major in...

Homework Statement A baby's mouth is a distance of 35.0 cm from her father's ear and a distance of 1.52 m from her mother's ear. Child Sounds <------------0.35m-------->Father X <----------------------------1.52m-----------------> Mother Homework Equations I(Father) =...

Suppose that you want to prepare 2.00*10^3 L of ammonia gas, NH3 , from the reaction of hydrogen gas with nitrogen gas. What volume of hydrogen and nitrogen do you need? Assume that the temperature and pressure remain constant during the reaction. 3H2(g) + N2(g) -> 2 NH3(g) V H2 =...

Homework Statement My question is in regards to a relatively simple problem: A massless, ideal spring with a spring constant k hangs from the ceiling; it is originally neither compressed nor stretched. We attach a block of mass m to the spring. In terms of the mass of the block, the...

When doing calculations, should pressure be in atm or Pa? (looking for answers in joules)

I have 5 values of data for flux, each were calculated using a 2% error in current. Should I put the uncertainty for the individual values or just give the standard deviation of all 5? Current 1 2 3 4 5 Flux...

Hi, please don't hesitate to reply to either of my paragraphs. Or ask for clarification. The first paragraph descibes the basic problem, and the second one is more indepth. I'd be happy if I could get just the first one working. I'm working on a project were a two-axis accelerometer will...

for my coursework I'm meant to do error calculations. say i measured a distance between two things five times and got these results: 0.104 0.104 0.104 0.108 0.108 now I've got to use this distance for my calculations. would you recommend i use an average (mean)? i suppose that's a...

I wish to find the value of .8^(2/5) using logs. I can find the value of .8^(-2/5) as follows: =(log(8)X1/10)X-2/5 =(-1 + .9031)X-2/5 = (-.0969)X-2/5 = +.03876; antilog(.03876) = 1.093; Now to find .8^(2/5) my approach is the same: log(.8)X2/5 = (log(8)X10^-1)X2/5 = (bar1 + .9031)X2/5 ...

Please someone check to see if on the right track: A woman lifts a barbell 2.0m in 5.0s, beginning and ending at rest. If she lifts the same distance in 10s, the work done by her is: I said it would be four times as much because I used 1/2mv^2. I placed the v I calculated from v=d/t into...