Recent content by nineeyes

Hi, Sorry, but we have not yet encountered this equation in my class. I was wondering do I differentiate with respect to A? If I do, doesn't that just eliminate the A from the equation? I was thinking I would need to somehow solve for A , in terms of T_H and the Power Output. Sorry if I...

Problem : Consider an engine in outer space which operates on the Carnot cycle. The only way in which heat can be transferred from the engine is by radiation. The rate at which heat is radiated is proportional to the fourth power of the absolute temperature and the area of the radiating...

Thanks a lot for the help! That's a really useful site.

Hi, I was wondering if anyone knew a site where I could find the superheated vapor tables for propane. It's not in my thermodynamics book and I spent some time searching online and couldn't find it there either. I really need it to find the specific volume (ft^3/lbm) for T = 80 F and P = 125...

I've been having some trouble with the following Question. { A rigid tank contains 90% by volume propane at -40 F. The tank is then heated to 80 F. A pressure relief valve in the tank is set at 125 psi. Will any propane be vented. If yes, how much? Tables for propane at...

Having trouble with a thermodynamics problem I'm having a bit of a problem with some of the homework in my thermodynamics class. Question (Water at 20 C, 100 kPa is compressed isothermally to 50 MPa. Determine the work required per unit mass. ) using the tables I found: State 1 T_1=20C...

I attached the problem and diagram. This problem has been bothering me a bit. A friend of mine told me I could solve for the stopping distance by just looking at the crate. I got x: \mu*N_w = M*a y: N_w-W_w=0 and from this got a=-9.66\frac{ft}{s^2} I used the acceleration and...

Yes, the pulley is massless in this problem. Thanks for the help!

Thanks, I used work energy and got this for the equation with the outer pulley connected to the glider. m_2*g*h=\frac{1}{2}*m_1*(v_1)^2 + \frac{1}{2}*m_2*(\frac{1}{2}*v_1)^2 where m_1 is the mass of the glider and m_2 is the mass of the tub of cement hanging over the side. v_1 is the...

A glider is attached to a bathtub full of cement via a double pulley system, (the bath tub is hanging over a cliff). Assume the glider rests on a freely rolling cart. I wasn't sure of exactly how a double pulley works. The picture shows the one where the Glider is attached through the outer...

Thanks, I figured out what I did wrong... The way the book worded the problem messed me up. They gave me the horizontal velocity, but the picture was top down... and basically I mistook the horizontal velocity for the x component of the throw, when it really was the magnitude. Thanks for your help.

A football reciever B runs the slant in pattern, making a cut at P and thereafter running with a constant speed v_B=21ft/sec at an angle of 30 degrees from the y-axis. The quarterback releases the ball with a Horizontal velocity v_A_x=100ft/sec the instant the reciever passes pont P. Determine...

Problem : A baseball player releases a ball with v_0= 100 ft/sec at an angle of \theta= 30 degrees. Determine the radius of curvature of the trajectory (a) just after release and (b) at the apex. For each case compute the time rate of change of the speed. I really wasn't sure how to do the...

Thanks for your help, I found the answer!

Hi, Someone asked my professor about this in class and he said we only need to use the equation y=y_0+(x-x_0)*tan(\theta)-\frac {1}{2}g (\frac {x-x_0}{v_0*cos(\theta)})^2 Once. He said that we need to put v_0 in terms of \theta. and find a \theta that would give a minimum value of v_0...