Unit Definition and 1000 Threads

Hello everybody Normally you say that the unit of torque is Nm but could also be (Nm)/°.? I'm claiming this because of the fact that you normally do not give radians any unit, and that is why you just write Nm and not (Nm)/rad. SI claims that: "torque may be thought of as the cross...

Homework Statement there is a surface xy3z2=4. What is the unit normal to this surface at a pt in the surface (-1,-1,2)?? Homework Equations what is a unit normal to a scalar region? how can it be calculated? The Attempt at a Solution i calculated the gradient (del operator) of...

Let's say I have 4163 kJ/mol of energy coming from a substance with molar mass 86.14g/mol. How would I convert the 4163 kJ/mol of energy to kJ/litre? Thanks.

In group representation theory, identity element's representation matrix is unit matrix. But why? Could you give me an exact explanation? Thany you.

So I've been reading about orientated surfaces lately, and I always see the definition that a surface S is orientable if it is possible to choose a unit normal vector n, at every point of the surface so that n varies continuously over S. However, what does "varies continuously" mean? I never...

Homework Statement Let z1; z2; z3; z4 be four complex numbers on the unit circle (i.e., |z1|=|z2|=|z3|=|z4|=1). It is known that z1+z2+z3+z4=1+i . Find the value of 1/z1 + 1/z2 + 1/z3 + 1/z4 Homework Equations 1/z = barZ/|z|^2 The Attempt at a Solution I've been trying for about a day now...

Hi to all experts! I know individually about primitive cell("It has lattice point at corners only") and unit cell("It has lattice point at corners as well as at center if bcc or at faces if fcc or at bases if it is base centered") Are these right? But I don't know what is Wigner-Seitz cell...

Homework Statement Find the maximum and minimum value of the function, defined over x2 + y2 + z2 \leq 1. x \geq 0, y \geq 0, y \geq 0. Homework Equations f(x,y,z) = xy(z+1) The Attempt at a Solution \nablaf = (y(z+1), x(z+1), xy) = 0 Gets me (0, y, -1), (x, 0, -1), (0, 0, z) and...

Hello everyone, I represent an iron & steel manufacturing industry which runs on electricity. Currently our electricity consumption is 1,000,000 units/month @ 5.5 INR/Unit consumed along with maximum kVA reached during the time of manufacturing of product which is affecting the costing of...

Homework Statement Solvinf the unit time step equation mathematically. Homework Equations x(t) = u(t+1) - 2u(t) + u(t-1) The Attempt at a Solution How can i solve this signal mathemtically :( and using plotted signals , i couldn't understand, here is my approach and I'm...

I am using an equation that states that critical sonic velocity is: a_{cr}=\sqrt{\frac{2\gamma}{\gamma+1}gR_{gas}T'} The units should result in velocity (\frac{m}{s}) Yet, when I do the unit reduction I do not get that answer. Here is what I get: Lets ignore the square root for now. Also...

Homework Statement "The gravitational constant G is 6.67*10^-11 m^3*s^-2*kg^-1. What is G in units of cm^3*s^2*g^-1 Homework Equations 1kg = 1000g 1m = 100cm The Attempt at a Solution I don't understand how the dimension can change from [L^3,T^-2,M^-1] to [L^3,T^2,M^-1]...

Homework Statement That is what I learnt, and that it is expressed in Newton*meter. Then I learned that G is equal to 6.47 x 10^ -11 joules and that h is equal to 6.6262 x 10^ -34 joules x sec (N*m*s)and that one photon of light (say red) is equal to 4x 10^ 14 Hz(frequency) and its...

I have one differential equation like dN/dt=c*(other terms with no unit) unit of c is 1/ns. Now if I solve this equation, I will get value of N corresponding to t. (1) Then what will be the unit of t? (2) and if I calculate dN/dt1=(other terms with no unit). where t1=t/c. Then what...

I have always been critical of the idea of Planck units. They seem to be something conjured from numerology - particularly in view of the fact that it is possible to arrive at diffeent values of the so called fundamental dimension(s) by combiing different constants. But I recently had reason...

Homework Statement The graph shows the vector-valued function r(t). It is given that r(1) = <-1,1> and r'(1) = <1,2>. Find the unit tangent vector T(1) and unit normal vector N(1). (the graph given is that of y = x^2 shifted 2 units left.) Homework Equations (1) T(t) =...

Largest Unit of Heat Energy? Which of the following is the largest unit of heat energy: (a) calorie, (b) Btu, (c) joule, or (d) kilojoule. I narrowed it down to kilojoule or btu. I think it is btu.

Hi I was wondering what the method/theory is behind selecting the size of an anaerobic digester in order to fuel a 500kW cogeneration unit? Any ideas? Thanks

Consider the hyperbola y^2-x^2=1 (y>0) a.) Find a parameterization for the curve and write it in vector form, R(t) (b) Calculate the unit tangent vector as a function of the parameter. (c) Calculate the unit normal vector and the curvature vector as a function of the parameter.

For a motor modeling project I am trying to find a value that is measured in Volts/kRPM (Voltage constant) , in the motor specs that I am given i have a value in RPM/Kv, If the value for RPM/Kv given is 245, how can i find Volts/KRPM, or is that even possible Thanks!

Hi to everyone. I'm detecting collision between two ellipses. I've got my unit vector, my ellipse center and radius (horizontal and vertical). I want to calculate the point that lies in the ellipse on the direction of the unit vector. See the image attached. Suppose the red arrow is my unit...

The 1968 alternator gauge is 'smoked' The replacement Stewart-Warner gauge is different - it reads "Amperes" instead of "Alternator". I would like to save the casing on my unit...There is a detent on the rim of the casing and looks to me like the main cap would "pop-off", like a watch case. If...

Homework Statement Consider an electron of mass m=9*10^-30 kg in an infinite box of dimension a=10^-9 m. What is the energy difference between the ground state and the first excited state? Express your answer in eV. Homework Equations E_n = \frac{\hbar^2\pi^2n^2}{2ma^2} The Attempt at a...

Unit four appears to me to have no significant details left unknown. This was a weak hydrogen blast. The hydrogen had accumulated slowly after electricity was lost and air circulation stopped. The upper portion of the building was becoming quite warm which was encouraging the chemical...

Fukushima - Unit 2, what happened different to Units 1 and 3? There are recent discussions about this topic going on, so I think it deserves its own thread. According to attachement IV-2, Unit 2 is responsible for more than 90% of the overall emissions. So there's one big question: What was...

finding the FT of x(t)=sin(πt) sin(50πt) : ( '*' is the convolution operator) its FT X(Ω)=(1/2π) F(sin(πt)) * F(sin(50πt)) = (1/2π) jπ(δ(Ω+π)-δ(Ω-π)) * (jπ (δ(Ω+π)-δ(Ω-π)) ) (a) from my professor's solution it next goes: = (π/2) (-δ(Ω+π)+δ(Ω-π)) * ((-δ(Ω+π)+δ(Ω-π)) )...

I have no idea what this box(relay) unit does. Can someone identify this beast and tell me what it does! It is a metal bracket with a lip that has 2 holes in it. On the underside are the electronics, diodes and stuff proteced by a removable box which is fastened to the unit with 2 screws. There...

Homework Statement Find a unit vector orthogonal to A in the plane B and C if A=2i-j+k B=i+2j+k and C=i+j-2k Homework Equations The Attempt at a Solution Im thinking the solution is to take the cross product of B and C. and that would be the solution??

Homework Statement The position on the ground in the xy plane that is hit by the sun given by (x,y)=(3t+tan(phi), -2t+tan(theta)), where t, phi, and theta, are controlled input variables. What is the velocity of the hit point if the input variables are at values (5, pi/4, pi/3) and changing...

Hello everyone, I have a practical problem I am looking to solve. In my tiny 300 sq ft apartment in NYC I have 3 windows with exposure to the East, West, and South. It is very hot. I just purchased an 8000 BTU window unit, so in which window will the unit operate with the most efficiency...

The SI unit "henry" Is a "henry" only produced by magnetic induction, in which case would produced one volt that allows the induction of one ampere per second?

The roentgen (R, also röntgen) is a unit of measurement for exposure to ionizing radiation (such as X-ray and gamma rays), and is named after the German physicist Wilhelm Röntgen. Adopted in 1928[1], 1 R is the amount of radiation required to liberate positive and negative charges of one...

Homework Statement L{2t u(t-1)} Homework Equations L{g(t) u(t-c)} = e^-cs L{g(t+c)} The Attempt at a Solution L{2t u(t-1)}=e^-s L{2(t+1)} L{2(t+1)}=2/s^2+2/s L{2t u(t-1)} = e^-s {2/s^2 + 2/s} i think the whole attempt is wrong , I'm getting confused in this type of...

Hello folks! You may have heard the theory put forth that the explosion at Fukushima Daiichi Unit 3 involved a nuclear reaction, or prompt criticality. There are at least three experts who appear to be supporting this theory. On being Chris Busby, who...

I am learning about the unit circle and I am a bit confused. So, I have my circle drawn with radius 1 and I sketched a right angled triangle inside it so that the hypothenuse has a length of 1. I think what is making me confused is the meaning of sine, cosine and tangent. They are...

Homework Statement which is unit is a unit of electrical power v/a a/ohms a^2/ohm v^2/ohm which unit is= to one joule v/m a(x)v v/c c(x)v thanks- the x is a multiplication sign Homework Equations The Attempt at a Solution

Hi! I am new here and I have come to feed and develop my curiosity in mathematics and sciences. School is not enough I guess... The ALU is the part of the CPU in which every instruction is executed, right? But I don't understand, the OS itself is a software in machine language, it is...

Homework Statement Unit cell of a crystal lattice is a parallelepiped spanned by the vectors u, v, w vectors have lengths of 1, 2 resp3 (le). angles between the vectors is [u, v] = pi / 4 [u, w] = pi / 3 [v, w] = pi / 6 Determine the volume of the unit cell. Homework Equations How do...

I have a simple question: can we assume that a photon is the basic unit of information? And the photon movement is the information flow? It seems strange, but wherever I try to find anything about information flow basics, there is no mention about photons. Shannon's or Mazur's information...

When you are modelling elements like tubes, the local x-axis is defined along the tubes length. If a unit vector for the z-axis is not applied, modelling softwares defaults to a coordinate system where the local zx-plane is parallel with the global zx-plane. I'm not sure what that means...

If I have units with degree Fahrenheit in the denominator can I cancel it with degree Rankine without a problem? Or do I need to use F + 459.xx to clear it? does 1/F cancel with R? I believe 1/F and R can cancel one to one, right...

Hello, :wink: I see for micro the Greek symbol μ - mu - is used. Then why don't it pronounced mu volts etc. instead of micro volts? Tell me the reason please. Many thanks for this. Cheers

Homework Statement f(t) = {0, if t<4 and (t-3)^3 if t\geq4 The Attempt at a Solution I feel like its pretty basic but i can't get it down I have u(t-4)(t-4)^3 Can i change it to u(t-4)^4? Then do i multiply it out and take the laplace? If someone can work it out for me that would...

Hi, Quick question, if anybody has any ideas that would be great. I am looking to allow a few small wires to pass into a hermetically sealed ECU enclosure on a small racecar. How can I allow wires in without compramising the fact its meant to be hermetically sealed (at least IP66)...

hi, i have trouble in understanding the concepts of the impulse response first of all, let's assume that we have a signal y[n] = x[n] which is time invariant and linear, hence if I understand correctly linear means that if for input a*x1[n] we have an output a*y1[n] b*x2[n] we...

How can I convert the voltge measured across a photodiode to light output or intensity or any other photonic unit? I am trying to measure the light intensity/output of some LEDs using a photodiode but the photodiode measures voltage as a function of light intensity.

I am trying to teach myself DSP, owing to bad lecture notes. In particular at the moment I'm trying to calculate impulse responses for LTI systems, given the system equation. I would really appreciate it if someone could tell me if my working and assumptions below are correct for the following...

Homework Statement For a material the stress is defined by the means of the stress matrix O O = (6 1 -2 1 2 2 -2 2 5) Expressed in MPA It can be derived that the principe stress are: O1= 4-sqrt(13), O2= 5 and O3=4+sqrt(13) I know you can derive the principal...

unit conversions!help! Homework Statement How do I convert Kilojoules to gallons? Homework Equations KJ to J to kg to g to L to gal The Attempt at a Solution I have 2.258 KJ (1000J/1) 2258 Joules. I am stuck here. How do i get from Joules to kilograms??

Hello Everyone, I have a small question bothering me. I wan to know whether the nabla operator has a unit? I am thinking it does and it should be 1/m. I just want to make sure whether this is true. Thanks! Jimmy