Rate Definition and 1000 Threads

Hi, I am not science student. Can anyone help me to solve this? Density and velocity of a fluid is given as 920kg/m3 and 5m/s, this fluid is flowing through an area of 25cm2. Calculate the mass flow rate? I am in search of some easy unite conversion tricks also.

Joan is riding her bicycle along a track at 15 miles per hour. Anthony, who is ahead of Joan on the same track, is riding his bicycle at 12 miles per hour. If it will take Joan 5 hours to catch Anthony at their current speeds, how many mile ahead of Joan on the track is Anthony? How would you...

In my textbook, it says that the rate of vaporisation can be increased by (a) increasing the temperature or (b) reducing the pressure. I understand why an increase in temp can lead to more molecules breaking away from the liquid and entering the vapor state. More temp = more energy = more...

Homework Statement A beam of ##^{50}##Ti nuclei impinged on a ##0.5 mg/cm^2## thick ##^{208}##Pb target in an experiment lasting 176 hours. During that time a total of ##3260 \; ^{257}##Rf nuclei were detected. The beam intensity was throughout the experiment constant at ##6.6\mu A##. Each...

Dear all, I'm wondering how a control valve can control pressure and flow rate. I understand that a control valve in a pipe induces a certain pressure drop but I don't understand how this affects flow rate. I'm disturbed with the continuity laws which states that the total flow rate between two...

Hey! :o We have that the differentiable function $u(t)$ is stricly positiv for all $t\in [0,\infty)$ and that $w$ is the continuous growth rate of $u(t)$. I want to show that $$w_u(t)=\frac{d(\ln u(t))}{dt}$$How is the formula for the growth rate? Is it maybe given by...

I recognize the rate of change of a vector in an inertial frame S can be related to the rate of change of the vector in a rotating frame S0 by the equation below taken from my textbook, where Ω is the angular velocity vector. $$\Big(\frac{dQ}{dt}\Big)_{S_{0}}= \Big(\frac{dQ}{dt}\Big)_{S} +...

Hi, initially I would like to express that if you look at the first question it asks the rate at which the production goes from up to down, and ıf there is a rate I think the result should include time unit, but when I look at the solution result only consists of numbers ( the multiplication of...

How to convert volumetric flow rate to mass flow rate?

Dear all, As we know, the reaction rate can be calculated as following: R = N * σ * Φ (1) Where R is reaction rate (events/s/cm3) σ is cross section (cm2) Φ is flux of incident particle beam (particles/s/cm2 N is density of target (atoms/cm3) Logically, there is a limitation of R, because...

Hello! 1. Homework Statement I need to find the instantaneous height of a liquid during the simultaneous filling and emptying (through a hole) of a cylinder. I have varying Qin at incremental time of 1 sec. with cylinder area=5 cm and orifice area=0.5 cm. Homework Equations Torricelli's...

This problem is actually for a program I'm writing and I've forgotten my basic maths.I have an initial value starting at period 0 . That value is 20. At the end of 12 periods (period 12) I have a value of 33. So I know the last value is 33 and the first value is 20 and I want to find the...

Homework Statement A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25°C, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to generate 5...

Hello people of PhysicsForum Apologies in advance if my prefix selection is inaccurate and for my absolute physics noobness. I know no physics jargon so I'm sure my question will be phrased in the same way a 10 year old might. So here is my silly, trivial question: First of all, remove all...

http://www.ox.ac.uk/news/science-blog/universe-expanding-accelerating-rate-%E2%80%93-or-it Now, a team of scientists led by Professor Subir Sarkar of Oxford University's Department of Physics has cast doubt on this standard cosmological concept. Making use of a vastly increased data set – a...

gee i am not worthy of being here with you guys but i must know is an accelerometer's negative output due to the braking of a motor vehicle directly proportional to the the rate of deceleration of the motor vehicle and can this be predicted using a derivative function? And if I were to plot the...

Homework Statement At a certain time, two radioactive sources R and S contain the same number of radioactive nuclei. The half-life is 2 hours for R and 1 hour for S. Calculate: (a) the ratio of the rate of decay of R to that of S at this time. (b) the ratio of the rate of decay of R to that of...

The Problem Statement I have a jet entering leaving a nozzle at ui into an ambient fluid with ue = 0 I am trying to equate the rate of momentum diffusement (or spread) to the shear forces caused by ue -ui I understand that the rate momentum diffusement is are equated by empirical K- values...

Homework Statement (a) What is meant by the statement that a solenoid has an inductance of 2.0 H? A 2.0 H solenoid is connected in series with a resistor, so that the total resistance is 0.50 Ω, to a 2.0 V DC supply. Sketh the graph of current against time when the crrent is switched on. What...

Is rate of collision and frequency of collision the same ? In what ways are they different ?

I am not a mechanical engineer; but I have physics background. I want to lift about 250 watts of heat from a metal block. At the same time I have to maintain its temperature at 30 deg Cel. For this I want to use water-air heat exchanger (HE). Heat exchanger will have inlet & outlet pipes. Hot...

Homework Statement You have to graph f(x) = x3 - 2x2 + x and find where the instantaneous rate of change is positive negative and zero. Homework EquationsThe Attempt at a Solution I factored this and found the zero's to be x= 0 and x = 1. With all this info given I graphed it and realized...

I observed that if you pour soda into a glass cup and leave the straw inside, bubbles seem to form on the plastic cup at a much much quicker rate. Why is this? Why do bubbles form on the straw at all? Not sure if this should be in general physics or chemistry

1. Homework Statement Hi. This is a problem related to designing a RC hover craft. We are given a datasheet for a fan used as thrust. http://imgur.com/6liZSid Sorry image post no working, url: http://imgur.com/a/6XLwL We have to approximate the equation to a straight line through the curve...

Hi All, I have a problem (with 3 separate instances) to which I believe I have the answers, but would like check with those more knowledgeable than myself. They revolve around 3 blocks sinking through water and which falls quicker. I am ignoring friction. Instance 1: All blocks are exactly the...

Homework Statement Kindly refer to part (c). The woking should be power/0.35 (what I think according to the graph). But the answer is power (that is the answer of part b) divided by 0.02 Homework Equations I have used the ratio method simply The Attempt at a Solution According to part (b)...

Hey, I have an air tank that is at a set pressure, say 3000psi, and I have attached a regulator to the end that regulates the pressure down to 800psi. As the valve on the tank is opened the pressure and the mass in the container will decrease. If there was no regulator the mass flow rate would...

I’m working on an experiment and would appreciate some guidance to characterize the performance of it. I have a small homemade copper coil submerged in a 3 gallon water tank. I’m delivering hot water to the coil that in turn heats the water in the tank. I sense I’m looking for a rate of heat...

Say you have a robot with mecanum wheels and move all the motors forward one rotation, and the robot moves forwards x cm. If you make the robot go sideways where each of the motors moves one rotation, does the robot move sideways x cm as well? Does it depend on the angle of the rollers on the...

Hi, We have a canister at a set pressure (4500psi) full of compressed air. A single stage pressure regulator is fitted to the canister that reduces the outlet pressure to 850psi. The flow from the regulator is then used in a divergent nozzle to create a thrust force capable of lifting a small...

Homework Statement Refer to the photo, please verify my answer Homework Equations calculus The Attempt at a Solution For c, can I do it by assuming Ah=V. A(dh/dt) + h(dA/dt) = dV/dt then find dA/dt?

Hello, We have a system with a 70 bar pump and 9 nozzles connected to the pump lines. Total flow rate is 2 l/m. Is there a way to change only one nozzle flow rate manually, with a pressure regulator valf just behind that nozzle? Thank you.

Hi, layman here, but hopefully reasonably educated. I did not know whether this question might fit better under relativity or under cosmology so I'm posting it here. General Relativity tells us that time slows down in gravity wells. The cosmic expansion tells us that the energy density in space...

Homework Statement You want to swim straight across a river that is 76 m wide. You find that you can do this if you swim at an angle of θ = 28° from the upstream direction at a constant rate of 1.5 m/s relative to the water. At what rate does the river flow? The angle θ is measured from the...

Good evening everyone, I have a pressure meter from where we determined a pressure drop of 5.5 psi (Initial pressure 45.5 psi, final pressure 40 psi). The working fluid is air. The diameter of one of the hoses that is connected to the pressure meter is 1/4". I wasn't able to take a picture of...

Hi all, I am learning about the vacuum Rabi frequency for the first time in Metcalf's book Laser Cooling and Trapping (Section 2.2). I am trying to make sense of the following two equations Metcalf gives: $$\hbar \Omega_{S} = -\vec{\mu} \cdot \vec{E_{\omega}}$$ and $$\vec{E_{\omega}} =...

Homework Statement First question on PDF: http://ars-chemia.net/Classes/102/Problem_Sets/Practice%20Exam%20for%20Exam%201%20Key.pdf Homework Equations I used the initial rates method: Rate2/Rate1=k2*[A]^m/k1*[A]^m The Attempt at a Solution When I solve these types of problems with the...

Hello, What is the fastest connection method (i.e. type of cabling) to transfer images from a video camera to a computer, i.e. what type of connection gives the highest frame per minutes? Is a USB connection fast? If not, why not? Should I look at a camera that connects in a different way...

Homework Statement Initially 5 grams of salt are dissolved in 20 liters of water. Brine with concentration of salt 2 grams of salt per lter is added at a rate of 3 liters per minute. The tank is mixed well and is drained at 3 liters a minute. How long does the process have to continue until...

Hi there, I am currently studying charge transfer reactions between metallic electrodes and redox couples in aqueous electrolytes (in a diffusion limited system), and I was wondering about the influence of the rate constant on the reduction/oxidation peak maximum. Typically, it is assumed that...

Everyone "knows" that \lim_{x\rightarrow ∞}\frac{2^x}{x^2} = ∞. We "know" this because 2x grows faster than x2. I use quotes because this is just what we're told in basic calculus classes. But what about a theorem for this? I've searched through google, looked through various university homework...

Homework Statement Certain pollutants encourage the following decomposition of ozone: 2O 3(g) -> 3O 2(g), at a rate of 6.5 x 10-4 M O 3/s. How many molecules of O2 gas are formed in each litre of atmosphere every day by this process? (As this problem provides a rate in units of mol/L/s and...

Hello, I am working with the mass flow rate equation which is:$$\frac{d \dot{m}}{dt}=\dot{m}_{in}-\dot{m}_{out}$$ To determine the change of the height of water in a reservoir. Assuming m_in = 10 and m_out = sqrt(20h), then : $$\frac{d (\rho \cdot Q) }{dt}=\rho \cdot Q_{in} - \rho\cdot...

If I have a tank of volume V, pressure P, and temperature T, what is the most effective way to determine the volume flow rate if I were to suddenly allow the air to discharge through a hose? My first thought was that I could use Boyle's Law to determine the compressed volume of air in the tank...

How these properties are related to velocity fluid. The https://postimg.org/image/674a6sw4t/ https://postimg.org/image/674a6sw4t/ figure shows an area of Earth's mantle where upwelling of hot semi-liquid mantle is occurring in middle and then two downwelling currents on two sides (forming...

Homework Statement A 1 meter long uniform line source of high energy photons emits 10^7 photons /sec. Calculate the particle fluence rate (flux density) at a point P 1m away from the midpoint of the source. Homework Equations ## dN = number~of~particles ## ## da = differential~area## ##\Phi =...

Homework Statement In some cases, the spectrum replication property of sampling can be used as a substitute for demodulation. Given a signal xa(t) with the spectrum shown, what is the lowest sampling rate that will ensure both no aliasing of the spectrum, and that one of the spectrum replicas...

Homework Statement Here http://imgur.com/a/4LRM6 2. Homework Equations The equation is given int he questionThe Attempt at a Solution gas will stop flowing when the pressure inside the gas is equal to that of the surroundings. I calculated the final mass of gas inside the cube. Then i...

What is the unit for energy transfer rate constant? I am confused because of the order of reaction of energy transfer. Consider the case for following energy transfer A* + C → A + C*. The star represent excited state. Then the rate equation for A* would be as follows: \frac{d[A^{*}]}{dt} =...

Good afternoon all, I am doing some back of napkin calcs for work and am having trouble finding an answer (or one that I can understand--its been a while since undergrad). We have a valve that has particular flow rate requirements to prevent unseating the valve seal. This is a mass flow rate...