Recent content by bkraabel

So if I get your drift, then the number of 6-element subsets (where the order of the 6 elements doesn't matter) in a set of 100 distinguishable elements would be 100 choose 6, which is 1.2 X 10^9. Is that the idea? thanks

Homework Statement An adsorbing filter allows gas particles to stick to locations on the filter surface. Once a particle sticks to a location, that location is filled. The filter can no longer remove gas particles when all locations are filled. Each 1.0 nm 2 of the filter surface has...

Ah - I guess the two ropes are not identical. I took "one rope" as meaning a single rope. So the wavelength can change if the ropes have different linear densities.

The problem statement says "moving your arm in such a way as to produce a harmonic wave with a wavelength of 1.0 m." Does that not means there is a single wavelength-frequency combination on the rope? Where would the other frequencies come from? thanks, Brett

Homework Statement You and a friend each have one rope. You tie the two ropes together and stand as far apart as possible, each holding one end of the new longer rope and pulling to put it under tension. You then begin moving your arm in such a way as to produce a harmonic wave with a...

I think it makes the engine a reversible engine because only a reversible engine can have the maximum theoretical Carnot efficiency.

reversible heat engine Ok, after further reflection, I think the device is working as a heat engine between the ground and the interior of the house. The "waste" heat is dumped into the house to keep it warm (1000 W) and the work (180 W) is used to distribute this heat. For a reversible...

Homework Statement In winter, you like to keep your house interior at 21.0 degrees C. Your geothermal heating system, which was advertised as being reversible, draws thermal energy from an underground reservoir at 347 K. In a cold winter, with the average outdoor temperature being 0.0...

Homework Statement Is there any position in an elliptical orbit where the tangential component of the acceleration is greater than the component perpendicular to the tangential component? If so, what conditions on the orbit must there be for such a position to exist? Homework Equations...

Homework Statement Let us explore whether there is any way to distinguish acceleration due to rotation from acceleration due to a gravitational force. Imagine a deep bowl with a small volume of milk in it. (a) What happens to the milk when you spin the bowl about a perpendicular axis that...

I guess that's my question: what arrangements am I missing for four vectors? Note that I tried my hand at five vectors just to see if that made it easier to spot a pattern -- it doesn't (at least for me). Anyone care to take a stab at the relationship between the number of vectors and the...

From the context of the book, I think that "treated as vectors" implies that you add them by arranging your arrows on the table top tip to tail. So, in this scenario, neither of these two patterns would qualify since they're not tip to tail (although mathematically they're correct).

For two vectors, how many unique ways can you arrange two antiparallel equal-length vectors (i.e., ways that cannot be made equal by rotating the arrangement of vectors)?? Seems to me there is only one way to do it (see attached drawing). All other possibilities are just rotations of the first...

Homework Statement (a) Suppose you have two arrows of equal length on a tabletop. If you can move them to point in any direction but they must remain on the tabletop, how many distinct patterns are possible such that the arrows, treated as vectors, sum to...

Duh! thanks...