Recent content by PICsmith

Haha! I've never heard of slugs before! And I'm in the US. Is that sad? When will we stop being so stubborn and just use metric units? And rename football to handball? As for your problem, it really depends on what your teacher wants. Though I'm guessing that's kilograms and not slugs.

Yes, use F(net) = m*a(up) = m*5.2 (as given in the problem). In addition, F(net) = the sum of all the forces acting on the box, which, as you said, is the tension (given as 58N) and the weight.

Well, if we're in a reference frame on the railroad car, there's three forces acting on the mass: gravity (downward), the "fictitious" force caused by the train's acceleration (to the left, not right...that's why the mass has swung to the left), and one more force that, as Doc Al said, is caused...

Yeah you're on the right path. Just remember that you have two masses, so you need KE and PE for both masses, before and after (8 terms). If you want to write out the complete equation, it's like this: (KE of m1 before) + (KE of m2 before) + (PE of m1 before) + (PE of m2 before) = (KE of m1...

Nevermind this statement...while yes they are different things, in this case they are the same velocity (the center of mass velocity in the frame at rest w.r.t. the ramp is of course the same as the linear velocity of the edge in the co-moving frame, since there is no slipping). You don't have...

Perhaps you are confusing the linear velocity from v=ωr, which is the instantaneous velocity of the edge of the rolling object, with the linear velocity of the center of mass of the object. Beside that, are you using the correct moments of inertia for the different objects? I'm assuming the...

Methinks you're forgetting the gravitational force.

If you don't know where to begin, try drawing a free body diagram in the rest frame of the mass, where the acceleration of the car is a force acting on the mass. What other force(s) are at play? Again, show what you've tried so far or tell us where you're stuck if you want more help.

So what exactly are you having trouble with? If you haven't tried to solve the problem or you don't tell us where you're stuck, you won't get much help. What are the relevant equations for conservation of energy problems?

I just want to point out that while Olde FORTRAN (77 and earlier) is indeed old and creaky (though still very useful), modern Fortran (90 and later) is comparable to the other languages mentioned, and is fully OO now. And as of the latest 2008 standard, it's the only language with built-in...

I'm pretty sure you're forgetting that mass is a function of time, so your integration of u*ln(M/m(t))*dt isn't as simple as you had hoped... Edit: Hint: Do the integration w.r.t. mass, and not time. The key here is that (I'm assuming) the fuel burn rate is constant, so dm/dt = -c, where c...

You've got breakfast burritos, bagels, burgers, crepes, pizzas, Hot Pockets, ... Why not sushi? Just Googled it. It's been done (of course). Looks good! I think bacon, sausage and scrambled eggs would be awesome in a roll. You could lays strips of bacon on the top, or ditch the rice and...

Be wary of advice from a self-proclaimed cynic! Though to be fair, a joyful one :smile:. But all joking aside, joyfulcynic made some good points. Though as I understand it, the large majority of researchers out there are not tenured (have a full professorship), as tenureship is becoming ever...

You'll have to introduce some phase/state variables to convert those two 2nd-order ODEs into four 1st-order ODEs, and then solve those. http://12000.org/my_courses/UC_davis/spring_2011/MAE_121_eng_dynamics/lab/lab_one/report/report.htm" (eqn 3 and the ones above it). Hope that helps.

No no, I meant that the x-axis should be defined parallel to the incline, along the direction of motion, as you did initially, but that you should take your angles w.r.t. that axis. You took a couple angles w.r.t. the y-axis (perpendicular to the incline), which isn't wrong, but mistakes are...