Recent content by MCS5280

Homework Statement Compare the deBroglie wavelength for an electron in the n=6 orbit of He+ compared to the n=2 orbit. Is the deBroglie wavelength the same, smaller, or larger? Derive this. Homework Equations Quantization of Paths of Electrons: 2 pi r = n (lambda) Bohr Radius: rn=n2 aB The...

Ok I think I am getting close to this one: c=\sqrt{\frac{2GM}{R}} M=\frac{c^2 R}{2G} Using the Heisenberg Principal: \DeltaX \DeltaP = \frac{h_bar}{2} \DeltaP = c M Solving this for \DeltaX \DeltaX = \frac{G h_bar}{c^3 R} How do I get the square root and get rid of the R...

Homework Statement a. The first part of this problem was to derive the escape speed (Vesc) for a star of mass M and radius R. b. The second part is where I am having trouble. It says to equate the Vesc calculated above and derive a formula for Planck length in terms of c, G, and h_bar...

Ok thanks for the help, just wanted to make sure I wasn't making a stupid mistake. Its so nice that my $120 textbook can't answer its own problems correctly. :mad:

I got the Y centroid coordinate to work out to the books answer, so that one is all good. Its just that the X centroid coordinate that I have calculated is 90.33 mm, while the book says it should be 87.3 mm. So is the book wrong? (I don't think rounding error could account for a 6 mm...

My calculations are for the X coordinate of the centroid with reference being the left edge of the shape. I divided it up into an 80x80 square for the left part, an 80x120 rectangle for the right with a semi-circle of with radius 40mm ontop of it. The cutout is a circle with radius 20mm. Its...

Homework Statement Determine The Centroid of The Area Homework Equations x_centroid = [(Area of each piece)(Centroid of each piece)]/(Area of each piece) The Attempt at a Solution This seems like a really basic problem, I am just reviewing for my statics final on saturday. The only problem...