Rate Definition and 1000 Threads

  1. D

    I Limits confusion -- What is meant by "instantaneous rate of change"?

    Suppose a particle is falling under the pull of gravity, the distance it has fallen is given by s=16t^2.Suppose we wish to find the instantaneous speed at t=1. Find the average speed between t=1 and t=1+h where h is any real number except 0. Distance traveled/Time it takes to travel the distance...
  2. S

    B Clock Ticking in Gravitational Well: Observation Rate

    I was wondering what someone standing far away from a planet with mass would see if he drops a clock towards the mass. And then vice versa if I was standing on the planet, what would I see. would I see the clock tick fast and then slow as it approaches? Thanks!
  3. S

    Looking to create a temperature rate of rise table for air

    How did you find PF?: Google l was asked how hot would our IT space get if we lost all air conditioning. The space is 20' x 15' x 10', We keep set point at 70 F and have 80 kW of load. Assuming this exists in a well insulate container with 20 racks of equipment. Doesn't have to be perfect but...
  4. E

    Theoretical reaction rate for water electrolysis

    So I'm designing a proces where carbondioxide is converted into methane using the Sabatier reaction. For this reaction hydrogen is required which I'm planning on producing using the electrolysis of water. But I'm having a problem where I need the speed of this reaction to determine the size of...
  5. A

    Coolant Mass Flow Rate Through Subchannel in Nuclear Fuel Assembly

    I am trying to find the mass flow rate of coolant through a channel within a hexagonal nuclear fuel assembly. I am given the specific heat of the fluid, the coolant inlet and outlet temperatures, the total power produced by a single fuel pin, the diameter of the fuel pin, the length of the fuel...
  6. K

    I Rate of change of ##L## in a rotating coordinate system

    * We've a vector ##\mathbf{A}## lying in space, changing according to some rule. * We introduce an inertial frame and find ##\left(\frac{d}{d t} \mathbf{A} \right)_{i n}## in it. * We also introduce a co located frame rotating with ##\mathbf{\omega}##. In this rotating frame I find...
  7. L

    What Is the Rate of Change of Acceleration at t=2?

    A particle traveled in a straight line in such a way that its distance (S) from a given point on that line after time (t) was S= 20t^3 -t^4 The rate of change of acceleration at time t=2 is what value?ok, I am kind of stuck on this very simple problem. It should be as simple as taking the...
  8. A

    Engineering Digital Communications: Bit Error Rate (BER), C/N, Constellations

    Problem Statement: I am not quite sure how to approach this problem and would appreciate the help. I how the C/N is closely related to the SNR (Eb/N0), but the question does not give the bandwidth or data rate for me to use the formula above. From the constellation diagram, my guess is this is...
  9. S

    Calculate the dose rate in a drum of U3O8

    Summary:: Calcul of dose rate. Hello everyone ! I have to calculate the total dose that an operator takes during different tasks in a workshop. . I must not use numerical software, so it's only calculous with the data I have. My question could be considered as stupid but the engineer in...
  10. Ophi-Siren-Kit

    Speed/Velocity and Volume Flow Rate of Viscous Fluids

    In my first attempt, I started off converting the radii of all three sections from centimeters (10, 8, 6) to meters (0.10 , 0.08 , 0.06), then used the VFR=Av formula to find the speed/velocity of section one. VFR== 0.063 m^3/s A== pi*r^2=pi*(10cm)^2=pi*(0.10)^2=pi*0.01 == 0.031415927 VFR/A=v...
  11. D

    I Steam flow rate in 2-chamber steam engine system

    Our system of interest has a duct on the left and a piston chamber on the right that make the shape of the letter T rotated 90º clockwise. The smaller tube on the left is abbreviated as P1 has an unspecified length while the piston chamber is P2. The air in P2 heats up and expands while the...
  12. laserdan

    A Rate and function to fill a theoretical vacuum

    I am trying to find a way to determine the rate and function that would describe how a theoretical vacuum (let's say a cubic centimeter) would repopulate with air if surrounded by ambient air at STP. Any suggestions? I am not very good with thermodynamic or kinetic theory. My current work...
  13. R

    How does a pump trade head for flow rate?

    A pump’s power is a product of its pressure rise times volume flow rate. Commonly, a pump is specified by giving the pressure rise, or head, it can provide and the flow rate, such as in gallons per minute(GPM). But some pumps provide the user with a chart that shows how the pressure rise can...
  14. N

    How Do You Calculate the Flow Rate of Oxygen in a Pressurized System?

    I am trying to calculate the flow rate of O2 from a known volume 25 in^3. The cylinder will fill up to a maximum pressure of 140 psi in 11.26 seconds. Any help to determine the flow rate will be appreciated. Do I use Bernoulli equation to find the flow rate?
  15. ergospherical

    A Rate of Change of Bondi-Sachs Mass: Derivation Reference

    If ##(u,v)## are null coordinates and ##S(u,v)## a two-surface of constant ##u## and ##v## then the Bondi-Sachs mass ##M_{\mathrm{BS}}(u) = -\dfrac{1}{8\pi} \displaystyle{\lim_{v \rightarrow \infty}} \oint_{S(u,v)}(k-k_0) \sqrt{\sigma} d^2 \theta## satisfies (Poisson, 2007)\begin{align*}...
  16. Edwardminett

    Heat Exchanger: +40C rise at 16 liters/minute flow rate

    Summary:: How to calculate the rate of heat transfer between hot external water and cold internal water in a pipe. The image attached is my attempt at the question however, I find myself stuck trying to work out internal and external heat transfer coefficient.
  17. C

    Oxygen Tank -- What if the person's flow rate is too high? (2l/min. vs 4l/min.)

    Covid is surging again due to the Delta Variant. I saw in the news of many oxygen tanks with people connected to them even outside in hospital tents. I'd like to know something. If a person accidentally given more oxygen than required, for example. 4 Liter/Minute instead of 2 Liter/Minute...
  18. chwala

    Solving this rate of decay problem -- Mass loss calculation

    My interest is on question ##11.ii## only. I think there is a mistake on the markscheme...i just need a second opinion on this...find attached the question and markscheme... markscheme here: it ought to be, ##e^{0.0277t}=1.6797##
  19. bhobba

    COVID Will a High Vaccination Rate Affect Contact Tracing?

    I heard an immunologist say the other day that once a high vaccination rate is achieved, contact tracing will likely not be effective. I can sort of understand why. Does anyone from places with a high vaccination rate know if contact tracing is still an effective measure? It is very widely...
  20. L

    Find Frequencies in Signal with Random Sample Rate

    Hi How do I find the frequencies in a signal obtained by samplings with a random sample rate? Normally I use a fft analysis, but then I have a fixed sample rate. Thanks!
  21. H

    What is the relationship between pressure and flow rate?

    I performed an experiment where I let water flow out of a measuring cylinder through a hole at the base of the measuring cylinder. I let the water run out for 30s, recording the volume after. I did this for different heights of water in the measuring cylinder, and kept the pressure of water at...
  22. DaveC426913

    Optimizing Flow Rate for Above Ground Pool Heater Installation

    I am having a heater installed for my 12ft round above ground puddle pool. The heater is a K-Star K-5 (5kW) heater. The manual says the heater's max flow rate is 8GPM and I'll need to install a diverter with a valve to bypass it until the flow is <8GPM. How do I determine what my current flow...
  23. brotherbobby

    Rate at which a bucket gets filled

    Problem statement : The problem statement is given above. I draw the image to the right. Note I have drawn the radii which is half the given diameters. Attempt : I wonder right at the start if the height of the bucket, 30 cm, is relevant. Though I am tentative, it is also clear to me right away...
  24. K

    Rate of reaction? (UV and heat)

    I remember when I was in high school, heat was very often said to be a factor of speeding up chemical reactions that we all know, because heat is actually energy, energy will excite the molecules and make them easier to collide with other molecules or leave its own molecules (breaking bond)...
  25. H

    Rate of energy dissipated by a power transmission line

    VR = IR = 400 [ 29*10^-6 * 800 * 10^3 ] = 9280 P = IV = 400*9280 = 3.7 MW I was able to calculate the correct answer from the above, but why can't I use the equation P= V^2 / R?
  26. T

    Inflation rate and discount rate?

    I have a payback for a project of 6 years without counting the inflation rate and discount rate. If the Payback is 6 years, how do you add an average yearly inflation rate of 2.10% and a discount rate of 5.75%?
  27. H

    Calculating Rotation Rate from Change of Angle

    If we know the change of angle is twice the incident angle, then the rate of rotation is 2*100 rpm = 200 rpm. Is there a better explanation of it?
  28. TheArrow

    Calculating Rate of Climb from T/W, L/D and Velocity

    Hello everyone, I'm trying to solve a problem from a textbook suggested by a fellow member here: To help me visualize the problem, I made the diagram below (not necessarily to scale or accurate, just an organizational aid): The textbook gives a simplified equation of...
  29. JD_PM

    I Pion Decay Rate: Verifying Decay Rate Formula

    I am studying the following process: pion decays (mediated by the charged ##W## boson) into a muon and anti-muon neutrino (i.e. ##\pi^- \to \mu + \bar{\nu}_{\mu}##). The Feynman diagram associated to it is And its Feynman amplitude is (where we of course neglected...
  30. P

    Rate of heat flux from from hot gas in a pipe to water outside

    I have solved the first 2 parts. For the 3rd part, I have obtained the equation: T(x) - T0 = (T1 - T0)e^(-Φx/fc), where f = fm in the question. How do I obtain that expression for H? Thank you!
  31. J

    Find rate of temperature change using heat capacity, density and area

    So first I found rate of heat change using the above equation, with T=883K, e=1, SA= 6*l^2=21.66 Now dQ/dt=746593.71 W Now I am not sure entirely what to do next. They give density so I likely have to get the mass from that, M=pV,=1.9^3*4037=27689.783 kg. My issue is that I don't know how to...
  32. I

    Chemistry What is the rate law for the reaction of NO and H2?

    My solution and question are in the homework statement due to some formatting issues. Thanks.
  33. I

    Chemistry What is the relationship between temperature and reaction rate?

    I think I should use ln(K2/K1)=Ea/R(1/T1 - 1/T2), and find K2/K1. I am given T1 and T2, but not Ea. I'm not sure how to continue. Thanks. (note: the answer is C)
  34. Cheesycheese213

    Electrolysis of Water -- Rate of Reaction?

    I'm so sorry if this is a bad question! I am doing an experiment measuring the rate of gas production (hydrogen) of the electrolysis of water, and I got myself a bit confused about whether I have been taking the correct measurements? I had originally thought that, since the "concentration" of...
  35. A

    I Is Heart Rate Invariant in Different States of Motion?

    just something i think about, maybe it difficult to answer. i know, from study, that any observer moving along his world-line - in any state of motion - will not himself notice any difference to the rate which time passes for him. example: his heart-rate will feel normal (well, so long as he...
  36. HoneyBee

    Chemistry Finding rate constant from pressure change in an experiment

    Is there any way that I can find concentrations and then find the rate constant, k? And, using them, make an Arrhenius graph to find activation energy (including the catalyst)? Any help would be much appreciated. Change in pressure was found using a Vernier Gas Pressure Sensor. The starting...
  37. R

    MATLAB Plotting Reaction Rate vs Temperature with MATLAB

    I know how to get fusion cross section plots from the exfor website but now I need to plot the reaction rate as a function of temperature. According to the image, I have sigma and E values as x and y data. How do I integrate using MATLAB .
  38. F

    I Why is the derivative defined as the limit of the quotient?

    Hello, The derivative ##\frac {dy} {dx}## "appears" at first glance to be just the ratio of two infinitesimal quantities ##dy## and ##dx##. However, infinitesimals are not really very very small numbers even if sometimes it is useful and practical to think about them as such. Infinitesimal are...
  39. Eclair_de_XII

    Given price of an annuity and its level payments, find the interest rate

    A 30-year monthly-payment mortgage loan for 300,000 is offered at a nominal rate of 0.072 converted monthly. Thus the monthly effective interest rate is 0.006 and the calculated monthly payment is 2036.36. (Calculate the payment (PMT) on your calculator and leave it there for the moment.) When...
  40. C

    Calculate flow rate in a tap and the height of a reservoir

    The possible answers are: (I do not know what is the right one) A. ##H=120m## , ##S=0.0131\frac{m^3}{s}## B. ##H=60m## , ##S=0.0231\frac{m^3}{s}## C. ##H=120m## , ##S=0.0231\frac{m^3}{s}## D. ##H=240m## , ##S=0.0231\frac{m^3}{s}## E. ##H=60m## , ##S=0.0131\frac{m^3}{s}## F. ##H=240m## ...
  41. M

    MHB What Are the Solutions to the System of Inequalities for Target Heart Rate?

    One formula for a person’s maximum heart rate is 220 − x, where x is the person’s age in years for 20 ≤ x ≤ 70. The American Heart Association recommends that when a person exercises, the person should strive for a heart rate that is at least 50% of the maximum and at most 85% of the maximum...
  42. F

    Calculating Flow rate for an oxygen system

    I'm struggling with calculating the flow rate for an oxygen system. There is a pressurised cylinder. This then joins onto a pressure reducer. Then travels down a length of pipe which branches off to 4 exits there is no restrictions on the exits it just goes to atmospheric pressure. I am yet to...
  43. SebastianRM

    Relating volumetric dilatation rate to the divergence for a fluid-volume

    in class we derived the following relationship: $$\frac{1}{V}\frac{dV}{dt}= \nabla \cdot \vec{v}$$ This was derived though the analysis of linear deformation for a fluid-volume, where: $$dV = dV_x +dV_y + dV_z$$ I understood the derived relation as: 1/V * (derivative wrt time) = div (velocity)...
  44. C

    Calculating Count Rate for Neutron Beam Detection

    Finding the neutrons per second. Uncluttering the question: ##P = 6 \times 10^{7} J/s, E_{1} = 149.7 MeV/event, A = 10^{-4} m^{2}, R = 5 m ##. Number of events per second = ##\frac{P}{E_{1}}## = escaping neutrons per second Area of ##5m## sphere around reactor = ## 4 \pi R^{2} ## Fraction of...
  45. B

    Sand drops on a conveyor belt at constant rate

    I can understand how it can be explained using the change of momentum to find the average force on the belt, then us $$P=Fv$$ to get the power. What I didn't understand is why the energy solution won't work. If in 1 second, sand with mass m has fallen on the belt and accelerated to speed v...
  46. C

    MHB Write function to model combined rate

    The assignment states: Pipe A takes 20 hours longer to fill swimming pool than pipe B. Together, pipe A and pipe B can fill the swimming pool in 30 hours. The assignment question I am stuck on is to write a function R(x) that models the combined rate of the two pipes in relation to the time it...
  47. russ_watters

    What is the leakage rate of my underground piping system?

    This is a situation I don't often deal with; I have an underground piping system that is failing a pressure test and losing pressure at a rate of about 1psi/min from 80psi. I'd like to calculate the leakage rate. The pipe is a simple 10" diameter, schedule 40 steel pipe, 500' long (0.365"...
  48. G

    Volumetric flow rate of nitrogen through relieving pressure regulator

    Hello all, I'm having trouble figuring out the volumetric flow rate upstream of a relieving pressure regulator used on a 1/4" OD nitrogen line. Upstream of the regulator P=100 PSIG and T=70F, while downstream P=80 PSIG and T=70F with downstream consumption at q=4 L/min or 0.91 SCFM (at std...
  49. sahilmm15

    Classical Rate the Quality & Difficulty of the Book

    HI! Can you rate the book i mentioned below in terms of quality of concepts and the problems given. What do you think about the difficulty of the book?(For a moderately beginner person). Thanks! The link is .. [Moderator's note: link removed].
  50. J

    Angular Momentum Problem: Rotation Rate

    First I found the moment of inertia, I=1.8(5.5^2+3.9^2+4.9^2) =125.046 Then I tried to find the rotation rate using the equation L=rotation rate*I rotation rate=3773/125.046=30.173 But the answer is suppose to be 21.263?
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