Recent content by CheesyPeeps

Homework Statement: An open tank with a rectangular side 1 m wide and 4 m high is filled with a liquid of variable specific weight, γ, with γ = 50 + 2y (N/m3), where y is measured vertically downward from the free surface. Find the magnitude of the force on the side of the tank. Homework...

Yeah, I see that now. I wasn't thinking at all about the moment arm, but once I spotted the fact that Tsin30 and the weight have different moment arms, I got it. Thank you again for your help! Statics has been driving me mad, so I'm really glad I understand this now :oldbiggrin:

Thank you so much! I got it! I drew the weight's force vector down from the middle of the beam, and when I did that, it finally clicked that the moment arm of the weight would be half the moment arm of Tsin30. I had been stressing over this question since yesterday - I'm so glad I understand it...

Thank you very much for your advice. I replaced the wire with a vertical wire equal to Tsin30, and then wrote that Tsin30-100kN = 0. That means T = 200kN, but I checked the answer to the question, and it's T = 100kN. Have I missed something? I have the moments/torque chapter of my textbook open...

Homework Statement Homework Equations ∑MA = 0, where A is the pin. Tx = Tcos150 Ty = Tsin150 The Attempt at a Solution I've drawn in the 100kN force of the beam's weight, and identified that ∑MA = 0. I attempted to find the moment arm, but really wasn't sure how do to it, or if it would even...

Thanks! From ΔG° = ΔH° - TΔS° I can see how ΔG° would decrease as temperature increases, making the ionisation more spontaneous.

Thank you! That link definitely helped. I hadn't realized that the dissociation of water was endothermic. My country's exam board calls these 'open ended questions'. They are always full of holes and the marking schemes are so vague that it can be very difficult to know how to answer them...

Homework Statement If the text is too small, it reads: 'A student measured the pH of water at various temperatures using a pH meter and obtained the following results: (table showing pH decreasing as temperature increases) The student was unsure whether the results were accurate or if the pH...

Okay, so I've factorised it and found that ##n^3-n## is always even and therefore always divisible by 2. In order for it to be divisible by 6, it must be divisible by 2 and 3, but I'm not sure how to go about proving that it's divisible by 3. EDIT: I looked up the divisibility rule for 3, and...

Homework Statement For all natural numbers n, prove whether the following is true or false: n3-n is always divisible by 6. From SQA Advanced Higher Mathematics 2006 Exam Paper Homework Equations I can choose from the following types of proof: Direct proof Proof by contradiction Proof by...

Good advice! I lost 7 marks out of 100 on the paper this question was from, and most of them were due to arithmetic errors that could've been avoided by using that strategy, so thank you!

Thanks for your reply! I looked back over my initial working, and there were definitely some careless mistakes made from rushing through the steps too quickly! I redid the problem, making sure that I didn't cut any corners or make arithmetic errors, and I got z = 2 + 3i. To get z = 2 + 3i, I...

Homework Statement I've used z* to mean z conjugate. Given the equation z + 2iz* = 8 + 7i, express z in the form a + ib. From SQA Advanced Higher Mathematics 2005 Exam Paper Homework Equations n/a The Attempt at a Solution I substituted a+ib and its conjugate in for z and z*, which, after...

Thanks! I suppose it does make sense that we don't write it that way.

The formula to find the total resistance in a parallel circuit is 1/R=1/R1+1/R2+1/R3, but wouldn't it be easier to use R=1/(1/R1+1/R2+1/R3)? I've only ever seen the equation written like that once before, and I'm wondering if there's a reason as to why it's never really used?