Recent content by ploppers

Even and odd subsets mean choosing an even amount or odd amount. For example, 4 choose 3 would be an odd subset while 4 choose 2 would be even. Thanks for the responses, that was exactly what I did to prove it algebraically, however, what would the combinatorial proof be? I've tried to solve...

Homework Statement Show that there is a one to one correspondence between even and odd subsets of the set {0, 1...n}. Homework Equations They want a combinatorial proof so basically a proof based on counting? Perhaps (n choose k) = (n choose n-k) The Attempt at a Solution I've...

Ahh thanks, I should have looked up the notation haha!

Homework Statement Let x* be an element of a convex set S. Show that x* is an extreme point of S if and only if the set S\{x*} is a convex set. Homework Equations (1-λ)x1 + λx2 exists in the convex set The Attempt at a Solution I'm not too sure what S\{x*}, I asssumed it was...

Thnx, I followed and ot the right answer :D Actually I used the wrong variables for my equations. My Vq/r is actually combining the F = (funky E)q with (funky E) = V/d. However, I still wonder why I would use the 10 cm for d. is the V always the same between 2 plates? That would make no sense...

Would you be able to show me how to properly solve this?

Homework Statement A ping pong ball of mass 3*10^-4 kg is hanging from a light thread 1 m between 2 vertical parallel plates 10 cm apart. When the potential difference across the plate is 420V, the ball comes to equilibrium 1 cm from one side of the original position. What is the tension of...

Ahh thank you. It makes a lot more sense to make the equation geared towards one object anyway :D

Actually, this is not a homework question, but more of a concept problem (Sorry I can;t follow the format). We are given that the force of repulsion or attraction between 2 charged objects can be represented by : Fe = (Kq1q2)/d^2. Does this mean that the sum of the force between both objects...

Anyone have a solution? Or did I make another mistake?

Homework Statement A person wants to move excess topsoil from his farm. He can hires a truck and driver for $60/h. The driver will take 30 mins to deliver a load of top soil. One person will take 40 h to load the truck with soil. Workers get $18/h (Including the time the truck takes). How...

I agree that Vxy can't equal Vx or Vy...however, I do have somewhat of a solution (Kinda sketchy :p): We know that wherever this 30 degrees point is, the Vx will be the same as the horizontal so it can be denoted Vy since Vx = Vy. To find the y component, it would be tan30*Vy (Soh Cah toa)...