I need help with this one. I don't understand why the trend is decreasing because V = IR, and R = ρL/A. So if ρ is increasing, then shouldn't R also increase and hence V also increase? I'm confused.
Last edited by leosco1995; 03-06-2012 at 12:21.
Last edited by Zishi; 03-06-2012 at 14:02.
I don't know how to solve this.. I know that tension is like when you pull something and compression is when you push it.. but I'm still confused because for me it's hard to tell from just looking at a point on the diagram.
I thought A was the answer, BTW.
Last edited by leosco1995; 05-06-2012 at 09:15.
Is that always the case? I mean, when you bend something the outside edge will stretch and inside edge compress? It is kind of hard for me to imagine it on a diagram.
(Original post by Stonebridge)
It's common sense really.
If you pull down on that weight, which parts will be stretched (tension) and which will be compressed.
The key is to remember that if you try to bend a bar, the outside edge stretches and the inside edge is compressed.
If you pull down on that weight, which way would you expect the two bars to bend?
If you don't mind, could you answer this question too? For this one, I've eliminated options B and C (B because it isn't a stationary wave and C because there is some displacement at point R), but I can't tell if it's A or D. How can you figure out the velocity and acceleration from a displacement/distance graph?
Once again, thanks a lot for all of your help.
Last edited by leosco1995; 05-06-2012 at 10:03.
Think where the
centre of gravity is for the water in the LHS before opening the tap. The PE of the water in the LHS depends on the height of the c of g. Not the total height of the water.
(Original post by leosco1995)
I hope you guys don't mind me posting all these questions..
I don't understand this one properly. If half of the water gets transferred to the other vessel, wouldn't only the height be halved? The total energy then lost by the water would just be mg * (h/2)? But the answer is mgh/4.
Think where the c of g is after opening, with half the water now there.
How much PE was lost?
Think where the c of g of the water now is in the RHS
How much PE was gained?
Last edited by Stonebridge; 05-06-2012 at 16:40.