Recent content by Hans Herland

That's quite possible. I'd guess that it's one of the things that the assignment wants me to check, whether the spool will climb, or stay in place when pulling it with force P. But I'm not sure how to handle the different situations. Are there different calculation methods when impending motion...

The problem doesn't specify that the spool has to be about to travel up the step in order for impending motion to occur, so I believe it spinning around its own axis would also apply.

Hmm, I did consider that at first, but it felt weird considering I can then "skip" a lot of the information that the assignment provides. For instance, would the assignment then need to provide me with μb, when it can be completely ignored in this case? If I understand you correctly, the task...

Homework Statement Determine the smallest force P that will cause the spool to have impending motion. Homework Equations Equations of equilibrium, and static frictional equations. ##ΣFx = 0;## ##ΣFy = 0;## ##ΣMb = 0;## ##Fsa = μNa## ##Fsb = μNb## The Attempt at a Solution My first...

This is really detailed, and well explained. This makes a lot more sense than the notes our lecturer uses. =) I understand what you mean with ##cos^2 x + sin^2 x = 1##, and it is a lot easier. There's only one part of the equation I'm a bit confused with in your method: ##sin x = \sqrt {1 -...

Yeah, I noticed I was misunderstanding what the book was saying. My lecturer showed me how it worked, and had a laugh when she saw the attempts I had done where I filled pages with calculations. =)

Would that make it: ##sin x = \frac {\sqrt {(a + b)^2 - 4ab}} {a + b}##? Or maybe it can be shortened into: ##sin x = \frac {\sqrt {a^2 - 2ab + b^2}} {a + b}##

Thanks, I have a tendency to redo my assignments wrongly because I felt the original, and often correct, answer was wrong. I'm a bit unsure as to how to use the ##cos^2 x + sin^2 x## part. For instance, for the next part of this task, I have to find the exact value of ##sin 2x## and ##cos 2x##...

Homework Statement Firstly, sorry for the probably weird title. I have no idea how to title this problem, but hopefully my explanation is better. =) Given $$cos x = \frac {2\sqrt{ab}} {a + b},$$ where x is in the first quadrant and a + b ≠ 0, ab > 0. Calculate sin x expressed by a and b...

I've marked this as solved. I had a talk with my lecturer for help on how to solve it. It was much easier than I was making it, as always. =) ΣMa = mg(0.3) - (100 cos30)(1.15) - (100 sin 30)(1.5) = 0 $$m = \frac {(100 cos30)(1.15) + (100 sin30)(1.5)} {(9.81)(0.3)} = 59.3kg$$ Thanks to everyone...

I'm having a bit problems understanding exactly what this means, which is probably caused by me not being a native english speaker. Could you explain what "consistent convention of positive directions" means? From what I understand from my textbook, we look at torque with the right hand rule...

I'll be honest, I'm not even sure myself how I determine the signs in some cases. I find it really confusing. The problem I encounter is that when I look at the formula, Fxdy - Fydx, and write it as: (100 cos 30)(0.65) - (100 sin 30)(1.2) = -3.7 So I get a negative number when calculating the...

You should re-check the 1.25 number, since that's still based on the time it would have taken for the stone to drop at the height it was thrown in. Remember that it now drops from a higher altitude, making the drop longer than before, and the initial velocity of the drop is 0. Since the stone...

This should give you the time it would take for the stone to drop if it was thrown directly towards the ground. Since the stone is thrown upwards, you'll need to find the time it takes for the stone to travel with initial velocity of 6.91, to impact velocity of 0 (where the stone starts dropping).