Search results

Thanks. I’m going to have to re-write some of the given data in that problem so the final answer isn’t so sensitive to small variations of Tdp. I’ll make sure that using 70F or 70.2F yields roughly the same answer.

@mcc515 @MikeGlass1969 Thanks for working on the double pane window problem. Here is my solution. I get -4F which is different from what both of you are getting. Let me know if you see anything wrong  

Mike, the "extended" Bernoulli equation is actually a statement of conservation of energy. as such, it is essentially this (for steady state): The rate at which energy enters a control volume = The rate at which energy leaves the control volume In this problem a control volume is defined with...

It might be a little quicker if you approach it by finding the instantaneous center of rotation for rod BC.

Correct.

That is correct. The actual answer is 43.5 ft/s

An indoor swimming pool room has a 6 ft × 4 ft double-pane, outside wall window with an effective R-value of 3 (°F ft2 )/(Btu/h). The R-value for the indoor air film is 0.2 (°F ft2 )/(Btu/h), and the convection coefficient for the side exposed to outdoor air is 12 (Btu/h)/(°F ft2 ). The indoor...

The manufacturing process of thin films on microcircuits uses a perfectly insulated vacuum chamber whose walls are kept at -320°F by a liquid nitrogen bath. An electric resistance heater is embedded inside a 1.5 feet long cylinder of 1½ inch diameter placed inside the vacuum chamber. The surface...

In the engine system shown, crank AB is 3 inches long and has a constant clockwise angular velocity of 2000 rpm, and connecting rod BC is 8 inches long. When angle α is 40 degrees, the velocity (ft/s) of piston P is most nearly: (A) 3.7 (B) 21 (C) 41 (D) 44

The critical load formula is derived by assuming that buckling will occur at that load, that is when P = Pcrit. Therefore, the factor of safety for buckling is defined as  Pcrit/P. Try it this way.

Correct. For buckling, the Factor of Safety is Pcrit/P.

Can you show your work?

Nicely done. Good work catching the error. Thank you.

That is the right approach. Could be a rounding thing. If you post your work (photo or scanned PDF) we can look at it and figure it out.

LOL why?

Correct!

Yes. That is correct.

This is true. @monty01 has beautiful penmanship. A skill that seems to be in decline...

Beautiful.  One observation: The spring constant is given in pounds-force per foot. The mass of the system was given in pounds-mass. Therefore, the calculation of the natural frequency is sqrt[ (18.33lbf/in) / (44lbm) ]  From your work it appears you thought the 44 were pounds-force (a weight)...

Happy Friday all. Brand new practice problem (also posted in the HVAC&R thread): The flow rate through the pipe system is 5,100 cubic feet per hour and the Darcy friction factor is known to be 0.02 through the entire system. Branch 1 is 3.5” ID, and Branch 2 is 5” ID. The total length of...