Recent content by TbbZz

Thanks. So, in other words, i, j, and k are simply labels given to values of Vx, Vy, and Vz to make it easier to keep track of them (i.e. not adding a Vx to a Vy) during calculations?

When are unit vectors helpful? It seems to me that it is simply a way to rewrite a given vector component, but with an extra, redundant letter (i, j, k). Thanks in advance.

Tom Mattson, I greatly appreciate the speedy and helpful assistance, I will inquire about this question from the teacher.

This was a quiz in real life. The teacher provided us with the work and answer for each problem. I uploaded the work and answer for this particular problem in an image file:

I am probably making a silly mistake, but for some reason, I am still getting -4.47kJ as my answer. 0.017 mol O2 x ( -790kJ / 3 mol O2 ) = -4.47 kJ Thanks again for the assistance, Tom Mattson.

Okay, so how does this look? 0.017 mol S ---- which produces 0.017 mol SO3 0.017 mol O2 ---- which produces 0.011 mol SO3 Therefore, the 0.017 mol O2 is the limiting reactant because using all 0.017 mol O2 only produces 0.011 mol SO3. What exactly do I do next? Thanks.

Homework Statement How much heat will be transferred when 0.54g of sulfur reacts with 0.54g of oxygen to produce sulfur trioxide according to the following reaction: 2 S (s) + 3 O2 (g) --> 2 SO3 (g) change in Enthalpy = -790kJ Homework Equations The Attempt at a Solution...

The people are considered identical. While I understand that 17C12 equals 6188, would you mind clarifying where the numbers came from? for the notation: nCr , I understand that the "r" equals 12; however, I'm not sure how you determined the (6+12-1) part. Thanks for the help.

No, they only watch one movie.

Homework Statement A group of 12 friends goes to a cinema complex that is showing 6 different movies. If the group splits up into subgroups based on movie preferences, how many subgroup combinations are possible?Homework Equations nCr nPr (we can use calculators) The Attempt at a Solution...

Thanks for the help HallsofIvy, Rudipoo, and VietDao29. I was able to solve the problem correctly using your advice.

Thanks for the help Rudipoo, your assistance is appreciated. I successfully solved this problem and another one. However, I am having difficulty on the problem after that. It is similar, but I can't seem to figure it out. I'm attaching a picture of my work so far. I'm not sure what to do next...

Homework Statement Prove that the Given Equation is an Identity: sin2A ------ = cotA 1 - cos2A Homework Equations sin(A+B) = sinAcosB + cosAsinB cos(A+B) = cosAcosB - sinAsinB tan(A+B) = (tanA + tanB) / (1 - tanAtanB) sin2A = 2sinAcosA cos2A = cos^{}2A - sin^{}2A...

Thanks for the help, rock.freak667 and HallsofIvy. I got it now.

Thank you for the assistance, I can't believe I missed that!