Recent content by sandpants

In the link posted, in (4) I understand that P and N are reaction forces. But taking the moment around the hinge they shouldn't be counted. All the other forces are taken around the hinge (L dimension is used). Taking it around half that dimension would make it into a couple, P = mg. Hence just...

I have; my questions stem from these workings. I would need an external model to confirm my own work. Otherwise I would be blindly do random things and accept them to be true.

Homework Statement I am trying to establish the the dynamics of an inverted pendulum for further analysis. I understand that this is a well known problem, but the governing equations in various sources are different and make it difficult to keep track of what forces are being applied on the...

It does give me exactly that. And that's for a 0.2m duct width. My question is whether this is waayyy too long or not.

I have an assignment involving a duct vent and turbulent flow. Flow enters a duct vent of a certain cross-section, it then reaches another section with a smaller area, at the beginning of which there is a horizontal plate that is radiating heat. It's a 2D problem. Fluid is Air, inflow T=20C...

It was a past examination task. I'm not particularly impressed by the Laplace transforms. I do see the convenience but I find it is mostly overshadowed by the need to be able to articulate numbers and expressions around very well.

Many thanks.

I think I've noticed where I've made the mistake: left hand side of the partial fractions. s+1=A(s+1)^2(s+2)+B(s+1)(s+2)+C(s+1)^3, not 1=A(s+1)^2(s+2)+B(s+1)(s+2)+C(s+1)^3 for which I calculated. EDIT: A=-1 B=1 C=1 Is what at I get now. x(t)=e^(-2t)+te^(-t)-e^(-t) which is equal to...

I have the following 2 problems to solve using Laplace. 1) x'' + 3x' +2x=e^(-t); with x=dx/dt=0 when t = 0 2) x'' - 2x' +10x=e^(2t); with x=0 and dx/dt=1 when t=0 Where x' is dx/dt and x'' is the second derivative against time. My attempts: 1)Using laplace I get...

I assumed that there must be a way to circumvent viscosity because the emphasis of the topic was the equation u=-1/4μ*(dP/dx)*(R^2-r^2) (for laminar flows). Knowing viscosity means you can find the velocity through reynolds number Re=ρud/μ which is kinda trivial. Only thing that's left is...

You are right about the diameter. Its 0.25mm. Non the less, if viscosity was given it would be awfully easy to get the velocity. Another thing is, no temperature is given, which it is a bit iffy to make an assumption about what viscosity to use. Is there no way to get it out of there?

Homework Statement A water injection line is made from smooth capillary tubing with inside diameter D = 25.0 mm . If the length of the pipe is 0.75 m and assuming laminar flow is present up to Re = 2000, find (i) the maximum average velocity at which the flow is laminar (ii) the pressure...

Indeed, the ratios match up and allow you to express them with n=γ. Thermodynamics is always like that - an answer under your nose at all times. But another issue is that the numerator does not match up. The expected form is r-1 when I get 1-r despite getting the same denominator.

Can you be more specific? Apply where? If it's adiabatic there is no heat - I do not understand how the process can be related to thermal efficiency.

The question: A perfect gas undergoes the following cyclic processes: State 1 to 2 cooling at constant pressure. State 2 to 3 heating at constant volume. State 3 to 1 adiabatic expansion. Deduce an expression for the thermal efficiency of the cycle in terms of r the...