# Search results

1. ### X-ray production and ionization energy

I am confused with the Kvp and Kep. I know that In the x-ray tube, after heating the filament and the electron cloud if formed, then the step-up transformer is going to increase the voltage and reduce the current to produce a high potential difference to that electrons will accelerate from the...
2. ### Amplitude relation with periodic time

Homework Statement Ql: Which sound wave will have its crests farther apart from each other - a wave with frequency 100 Hz or a wave with frequency 500 Hz? Homework Equations Frequency= 1/ periodic time The Attempt at a Solution I did it like that: I just found the periodic time for each...
3. ### Ideal Gas Law and pressure

Homework Statement An ideal gas has a molar mass of 40 g and a density of 1.2 kg m-3 at 80°C. What is its pressure at that temperature? Homework Equations PV=nRT R constant= 8.314 n= number of moles T= tempreture in kelvin density=Mass/ Volume The Attempt at a Solution i simply solved it like...
4. ### Rotational moment of inertia for 3 balls on a pipe

this is really so disappointing, unfortunately
5. ### Rotational moment of inertia for 3 balls on a pipe

wow, I don't think i am gonna get this now, anyways, thanks everyone.
6. ### Rotational moment of inertia for 3 balls on a pipe

i am really surprised how could this be wrong, but this is in our lecture notes (college) and it's only 4 hours left for the exam. so is it hard to learn the parallel axis theorem
7. ### Rotational moment of inertia for 3 balls on a pipe

so how am i supposed to solve it. i am so confused really
8. ### Rotational moment of inertia for 3 balls on a pipe

yeah i understood that the text says , it will rotate in the plane of x-y. but to make sure, it will move like a pin wheel right? and what about the R so? which R should i take?
9. ### Rotational moment of inertia for 3 balls on a pipe

so the radius of the big sphere + 2.5+ the radius of the center sphere?
10. ### Rotational moment of inertia for 3 balls on a pipe

you mean it will not move like a pinwheel?
11. ### Rotational moment of inertia for 3 balls on a pipe

yeah the sysytem will be rotating around z ( perpendicular to the page) as we have (x,y) fixed point, so the system will be rotating in the plane of x and y but around z. so the axis of rotation z is perpendicular to the pipe and at the center of it, so that why i used 1/12.
12. ### Rotational moment of inertia for 3 balls on a pipe

Homework Statement Homework Equations The Attempt at a Solution i just dont know from where to take the R which is colored with brown, in the 2(MR^2), what is the R here exactly, because i took the radius of the sphere , but i get different answer althought it's near.

14. ### Rotational inertia hoop around a central axis

could this be right by any chance?
15. ### Will it rotate?

thanks thanks thanks very much sir
16. ### Will it rotate?

and regarding the pivot point, i think it's the one who will decide if it will rotate or not, i mean if it was at the center of the rod than there should be not rotation, but if the pivot is not in the center (not mentioned) then the distance of each force to the pivot won't be same so then i...
17. ### Will it rotate?

ohh yeaah, thanks everyone. i didn't focus on that point that is layning in the table! so okay, i got the idea of the total f is equal to zero by the two forces, but still, why we have a torque??? why there is rotation when the two forces are with the same magnitude and opposite to each other...
18. ### Will it rotate?

Homework Statement Homework Equations torque= F*r*sintheta total force on y= 0 The Attempt at a Solution how come it will rotate in this situation?? espicially that he is ignoring the weight force of the rod! i knew that i ignored the mass of the rod when he said total force on y= F -F. if...
19. ### Rotational inertia hoop around a central axis

i thought that these are circles or (discs shape) because our professor said he will be providing us with necessary laws of MoI for each shape found in the diagram. so i said there is nothing other than the circles to make the hollow cylinder shell shape so that we use (I=MR^2). or is it that...
20. ### Rotational inertia hoop around a central axis

would you mind explain it more, i don't get which common squares you are refereing to?
21. ### Rotational inertia hoop around a central axis

also, would you mind suggesting to me any useful videos on youtube or whatever about similar problems? or even a book including such problems, because i searched for somehow same ideas but couldn't find, it would be nice from you sir to help with it
22. ### Rotational inertia hoop around a central axis

okay, but what i don't get is what is the mass of the rectangular. now imagine i am working on the upper segment. the mass would it be 4kg?? i don't know really if the 4 kg is the mass of the whole rectangular or only the mass of the part of the circle which is included in the segment itself! if...
23. ### Rotational inertia hoop around a central axis

what about the mass of the rod, what will be the value I am gonna substitute in the 1/12(m)(l)^2 ??? and am I gonna separate the rods into three segments?
24. ### Rotational inertia hoop around a central axis

do you mean both have same formula? if yes what is it?
25. ### Rotational inertia hoop around a central axis

Homework Statement Homework Equations I= mr^2 for a hoop around a central axis I= 1/12 (m)(l)^2 for thin rod about axis through center perpendicular to lenght The Attempt at a Solution I am totally confused. i said first that the three masses each will make a hoop shape so i found I=mr^2...
26. ### Static equilibrium: Find the tension in a support cable

yeaah, It's not easy as i thought. it's not even right to say : Tsin30 = Mg-mg+F (F is the no known force) and i know that T= 2943 N from the sum of torque so trying to find F i get : F= -981 N does this indicates that the force is up or down. i assumed first that it would be down. since i got...
27. ### Static equilibrium: Find the tension in a support cable

then how do i know the opposite force ?
28. ### Static equilibrium: Find the tension in a support cable

yeaah, i got what you mean. i am taking the hanged plate as the body being balanced so : i computed T from the Sum of torque and got T equal to 2943 N which is definitely correct. and so i applied here sum of fy=0 and found T as if it's unknown and got T= 4905 N which means it's not...
29. ### Static equilibrium: Find the tension in a support cable

Homework Statement Homework Equations Σtorque = 0 Σfx=0 Σfy=0 torque= F r sinθ (θ is the angle between the r and the F) The Attempt at a Solution OKay, now i know how to solve this, but it's like i asked myself, how to know if this is a question that i am supposed to use Σfx=0 and Σfy=0...
30. ### Incline with friction and two blocks

Thanks i got it just few seconds before you reply :smile: