Recent content by HJKL

Ok. So M = F*a and in this case a is x? Then I get M = F*x. I already know F from problem a). In the solution it says xF * F = integral of x * dF, why is that? And what are the two x's?

Hey! Can somebody explain problem b)? I don't know if it's called point of attack, and I can't find anything when I search for point of attack. But it's the point where the resultant force acts, right? How do I find that?

Ok, thanks. So when I've got my equation and I then I'm supposted to find the constant. Why do I do this: I find the concentration of H3O, SO42- and HSO4-. But why is the concentration of HSO4- equal to 0.01 (moles of NaHSO4) - 10-2.194 (concentration of H3O and SO42-)?

Why do we write that first equation? And why do we get what we get in the second equation?

Solution: NaHSO4 ---> Na+ + HSO4- HSO4- + H2O <--> H3O+ + SO42- Moles of NaHSO4 : 1,2g / 120 g/mol = 0.01 mol [H3O+] = 10-2.194 [SO42- = 10-2.194 [HSO4- = 0.01 - 10-2.194 Acid dissociation constant: ka = 10-2.194 * 10-2.194 / 0.01-102.194 ka = 1.14 * 10-2 M

Hi! I've got this problem: 1,20 g of NaHSO4 is dissolved in water to 1,0 liters and pH=2,194. What is the acid dissociation constant for HSO-4? I assume I have to start with writing the balanced reaction, but I don't get how I do that. I know that I'm supposted to start with NaHSO4 + H2O , but...

I was a bit confused about which angles goes with which side, but I get it now. Thank you!:smile:

Oh! No, its not that. I just wrote it down wrong here:smile: I've used c^2 = a^2 + b^2 - 2ab * cosθ, and I get the first part right. I just don't get why I'm supposted to use this equation β = cos^-1 ((EC^2 + EA^2-EB^2)/(2EC EA)) to find the direction.

Homework Statement Two charged balls are placed in point A and B and the distance between them is 9,54cm. Each of the balls are charged with 8,0 x 10^-8 C. Find the scalar value and direction of the electric field in point C placed 5 cm from A and 6 cm from B. Homework Equations Cosine Rule...

Ok, now I understand. Thank you!:)

Is A the area of that rectangle then? Why do we part it up like that and use dx and dA? And is there an original equation or is dA = l dx the original equation?

No I didn't really understand any of it, but I see now. Thanks:) I still don't understand why we use that equation though. And what it means.

Homework Statement : [/B] The cross-sectional profile of a dam is shaped as an isosceles triangle. The dam is standing on horizontal ground and the watermirror is as high as the top of the dam. The dam has height h, length l and the distance from the bottom to the watermirror along the dam's...