Diameter Definition and 508 Threads

Looking at the ultra deep field view from the Hubble as shown here: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/deepfield.html#c1 Just by observing this picture is not evident the effect in the apparent angular size expected from redshifts z of about 1.65.(According to the L-CDM model...

What should be the minimum base diameter of a 1 meter cylindrical pole ? What should be the minimum base diameter of a 1 meter cubic pole ? how are these computed ? Does length of the pole impacts the base diameter ?

Homework Statement The moon Titan has an angular diameter of 4.4mrad as seen from the surface of Saturn. The sun has an angular diameter of 9.3mrad as seen from the surface of the earth. Which of the following eclipses cannot be seen from the surface of Saturn (a) A lunar eclipse of Titan by...

Maybe this is stupid question, but I am not sure how to get the diameter of the star cluster, I assume from the RA and Dec. I googled it and tried to come with a realtion between the RA , Dec and Diameter from Andrea's proposal but couldn't figure the correct answer This is all I find (see...

Homework Statement Value of the Van der walls constant for the oxygen is 32 cubic centimeter. Find the diameter of the oxygen molecule? Homework Equations thermodynamics problem The Attempt at a Solution

Homework Statement Polonium has a simple cubic structure at room temperature. Given that the mass density of solid ^{209}_{84}Po is 9.2gcm^-3 , calculate the diameter. The Attempt at a Solution Volume = mass/density = 209/ 9.2 = 22.7 cm^3 1 mole = 6.02 x10^23 mol^-1 22.7 / 6.02x10^23 = 3.77...

Homework Statement During a total solar eclipse, your view of the Sun is almost exactly replaced by your view of the moon. Assuming that the distance from you to the sun is 400 times the distance from you to the moon, find the ratio of the Sun's diameter to the moon's diameter. Homework...

Homework Statement The pressure inside a tank of neon is 150 . The temperature is 25C. how many atomic diameters does a neon atom move between collisions? Homework Equations I used the number density N/V=p/KbT and the mean free path equation, where pressure is in pasquals, and tried...

so, I'm taking up a course on electrical machine design and our professor gave us the equations for computing the different values required for a given specification. here is my problem: given these two equations: laD^2 = (W/N)(6.079x10^8)/(Byqr) --> eq. 1 and la = pi(D)(r)/(pK) --> eq. 2...

How do you determine RPM when given your velocity and the radius or diameter of the cirlcle? thanks in advance.

You can obtain a rough estimate of the size of a molecule with the following simple experiment: Let a droplet of oil spread out on a fairly large but smooth water surface. The resulting ”oil slick” that forms on the surface of the water will be approximately one molecule thick. Given an oil...

I have already asked the question of piston diameter size and efficiency in an earlier thread but i'll recap. My question was that is it true that the larger diameter piston have a larger propensity to overcome the mechanical loss of fricition due to the piston rings contact with the mating...

Homework Statement A fire-hose must be able to shoot water to the top of a building 35.0 m tall when aimed straight up. Water enters this hose at a steady rate of 0.500 m³.s¯¹ and shoots out of a round nozzle. (a) What is the maximum diameter that this nozzle can have? (4 marks) (b)...

If a pipe separates into 2 pipes, one with 1 m diameter (pipe A), and the other 0.5 m diameter (pipe B)... which tube has the higher pressure. From the continuity equation, we know that velocity decreases as area increases. So I know that pipe A has lesser velocity than pipe B.

Homework Statement A thin, 50.0 g disk with a diameter of 8.00 cm rotates about an axis through its center with 0.190 J of kinetic energy. What is the speed of a point on the rim?Homework Equations C = \frac{1}{2}MR^2 K_{rot}=\frac{1}{2}I\omega^2The Attempt at a Solution Since the formula for...

the foot operated sewing machine shown below has a driver pulley which is 30cm in diameter and is attached by a belt to a sewing pulley with a 5cm diameter. The sewing machine makes one stitch for each revolution of its sewing pulley. a. The driver pulley is turned easily at one revolution...

Homework Statement A line meets the coordinates axes in A and B. A circle is circumscribed about the triangle OAB. If m and n are the distances of the tangent to the circle at the origin from the point A and B respectively, the diameter of the circle is: (a) m(m + n) (b) m + n (c) n(m...

1. Homework Statement : The center of a 1.00 km diameter spherical pocket of oil is 1.20 km beneath the Earth's surface. Estimate by what percentage g directly above the pocket of oil would differ from the expected value of g for a uniform Earth? Assume the density of oil is 8.0*10^2 (kg/m^3)...

Design of heating element: Supply Voltage: 220V/3Ph/60HZ, Power: 9KW Resistance= VXV/P= 220X220/9000= 5.4 Ohms, But when physically when measure the resistance of wire using multimeter it is showing 17 ohms. Can you explain why there is differnece in practical and theortical value...

Not really homework, but I guess it's a "textbook-style question", so I'm putting it here. Homework Statement Suppose (X,d) is a metric space, and consider an open ball B(x,r)=\{y\in X|d(x,y)<r\}. The diameter of a subset E\subset X is defined as \text{diam\,}E=\sup\{d(x,y)|x,y\in E\}. I...

This may be an elementary question, but I am still in the elementary stages of physics. My question is this: if you have a 4" fan at the end of a 4" pipe which is sucking air through the pipe, and the pipe narrows to 3" about 24" from the fan, does the 24" section of 4" pipe experience a vacuum...

1. A standard 100 W (120 V) lightbulb contains a 8.50 cm-long tungsten filament. The high-temperature resistivity of tungsten is 9.0*10^{ - 7} ohm*m. What is the diameter of the filament? 2. p= resistivity, E = V/L, I = AV/pL, R = pL/A... 3. I know that I'm going to solve for A =...

hello everbody Can you please tell me why the potential energy affects the diameter of a splash. I know that if the height from which the water drop is fallen increases the potential energy increases as well. And when the drop falls the diameter gets bigger and bigger each time I increase...

Hi guys, Please help me out, I have a project here I need to design a pipe network system using Hardy Cross method. I have drawn my pipe network and done my distribution of the flow rate according to the give discharge. but now I'm not sure which method I should use in selecting pipe...

Suppose you wish to fabricate a uniform wire out of 1.0 g of copper (Density of copper is 8.93 x 10^3 kg/m^3). If the wire is to have a resistance of R = .5 ohms, and all the copper is to be used, what will a) the length and b) the diameter of this wire? R = .5 a weight of 1.0...

Suppose you wish to fabricate a uniform wire out of 1.0 g of copper (Density of copper is 8.93 x 10^3 kg/m^3). If the wire is to have a resistance of R = .5 ohms, and all the copper is to be used, what will a) the length and b) the diameter of this wire? this has me tottally confuzed...

Homework Statement A star of mass 1.81×1031 kg and diameter 8.10E+9 m rotates with a period of 25.0 days. Suddenly the star changes size, and rotates with a new period of 18.0 days. Assuming a uniform density both before and after the size change, what is the new diameter of the star...

Homework Statement This question is about the heated front windscreen of a car The heater consists of resistance wires which are embedded in the glass A) The power of the heater needs to be 180W for a satisfactory demisting A car battery of Negligable internal resistance supplies 12V to...

Hello there, I'm wondering if there is any restricting reason why fiber optic cables are not made thicker. Regardless of the practical applications, is there any reason you can't make a fiber optic cable that is only 2m long but 2cm thick (compared to the normal 0.0125 cm thick)? Does width of...

Why do we take pi as the ratio of the circumference to the diameter, and not diameter to the circumference? Is it because circumference is always bigger than the diameter, so that it will be easy to work with the ratio? Or is it something fixed by those who discovered it and we can't change it?

Homework Statement Given a cyclic quadrilateral with side lengths 1, 2, 3 and d (in that order) where d is the diameter of the circle, find d. The Attempt at a Solution I tried using Ptolemy's theorem and Brahmagupta's formula, but to no avail. Can I get pointed in the correct...

I only have one example that I can find, and that's finding the diameter of a copper atom. Do most elements follow these steps? 1.) Make sure density is in kg/m^3 2.) find number of copper atoms in a 1 meter by 1 meter cube. 3.) find number of atoms in one edge(row?) of said cube. 4.)...

Homework Statement If 49 m of nichrome wire is to have a resistance of 16.0 ohms at 20 degrees Celcius, what diameter wire should be used? Homework Equations R = \rho x L / A A = \Pi d^2 / 4 The Attempt at a Solution well i know what I'm looking for, that is d (diameter) and d =...

I am attempting to build an intake setup for an engine I'm working on. I currently have a 3" diameter aluminum pipe on the throttle body that just curves off to the side. I would like to try and get some cooler air by routing it down into the bumper. I have access to 2.5" diameter piping. I was...

Homework Statement a planet is 5x10^8 km from its sun, from the planet, the sun has an angular size of 1 degree. what is the diameter of the sun? Homework Equations The Attempt at a Solution ive drawn a diagram with the sun and the planet, with the distance between written in and...

Homework Statement A 54.0 kg cheerleader uses an oil-filled hydraulic lift to hold four 130 kg football players at a height of 1.40 m. If her piston is 18.0 cm in diameter, what is the diameter of the football players' piston? Homework Equations The Attempt at a Solution 54...

Hello there, Im trying to figure this assignment question and I have hit hurdle. Can someone please help with figuring out what the velocity and pipe diameter will be?? Question: In a plant 20m3(cubic)/h of water at 20 degrees C is to flow via gravity from a storage tank to another one...

Hello there, Im trying to figure this assignment question and I have hit hurdle. Can someone please help with figuring out what the velocity and pipe diameter will be?? Question: In a plant 20m3(cubic)/h of water at 20 degrees C is to flow via gravity from a storage tank to another one. the...

Im trying to find an equation for a helix that gets wider and thinner yet the angle of all the coils remains constant. Is this possible? Any ideas? Thank you! PS - I am not a math expert, but throughly enjoy the process! walt

Homework Statement Find the minimum diameter of an l = 17.2 m long steel wire that will stretch no more than 7.38 mm when a mass of 323 kg is hung on the lower end. (Hint: The Young's modulus of steel is 200.0 GPa.) Homework Equations Youngs = (Force / Area) / (change L / L)...

If there was a stick the length of the diameter of Earth spinning in space for the same amount of time at the same rate as earth, would it appear as a spiral?

If I had a circle with diameter X and I twist the circle into a figure eight how could I calculate the diameter of one of the resulting approximate circles?

Homework Statement if the diameter of wire is doubled will there be any change in length of wire Homework Equations The Attempt at a Solution

Why does the wavelength of light have to be longer (or shorter?) than a hole diameter to pass through the hole? Also, is this phenomenon the same reason AM radio signals cannot be picked up as well FM radio signals when driving under an overpass?

Hi gurus, I was hoping you guys can help me with a little something: I have just purchased a 12V DC motor with a shaft diameter of 5.4mm (Oddly enough, the description on the ebay page says 5.5mm, but the technical drawing attached, says that its 5.4mm). In any case - i am looking for...

I am trying to find the flow through a pipe between a pump and an outlet I know -gauge pressure just after the pump -pipe diameter -pipe length -elevation change Any idea how to go about this?

Homework Statement During a total solar eclipse, your view of the Sun is almost exactly replaced by your view of the moon. Assuming that the distance from you to the sun is about 400 times the distance from you to the moon. Find the ratio of the Sun's diameter to moon's diameter.Homework...

Hi Firstly, this is not a homework problem. It's regarding some flow experimental results I have and to understand the results further I am trying to identify possible reasons for the patterns I see. I don't have expertise in thermodynamics hence finding the following problem a bit puzzling...

Hi, Have a query on the back focal plane diameter of an objective. I have got an equation back focal diameter = 320mm X NA / M where NA is the numerical aperture and M is the magnification. Just wondering is there any explanation for it? Thanks

Dear Forum, I am currently trying to buy some imperial machine screws and bolts online, and I am confused with how the diameter is given. The website I am seaching (boltdepot.com) gives me these diameters but I don´t understand what is meant by i.e. "2-56" 2-56 4-40 6-32 8-32...