Recent content by mysci

In fact, I don't understand although I can deduce it. The volume of sphere is (4/3)πR3, (πR2 x dz) = base area x height = volume of cylinder Whether I got wrong about the picture is talking about the cylinder not sphere? Thanks.

σ=Q/ πR2 and ρ=Q/ V Then ρ=Q/ (πR2 x dz) in here?

dE = ke(dq/r2) How to change to complicated equation in the following picture?

Thank you.:wink:

Thanks. Then I got following, absinΘ = |axb| ccosΦ = n·c Is it right?

By the way, how do you type the vector symbol in here? I can't find this symbol. Thanks.

I may get something. In fact, absinΘ = |axb| ccosΦ = n·c Is it right? I thought absinΘ = |axb|n and ccosΦ = c before I get the above thinking.

Thanks. Yes, but why not |axb|, is |axb|(unit vector n) in third step? absinΘ and |axbl are also magnitudes, but |axb|(unit vector n) is a vector. absinΘ = |axb| ≠ |axb|(unit vector n) = vector a x vector b. However, here absinΘ = |axb|(unit vector n). I don't understand this. On the other...

We know the rule of cross product or Why here |absinΘ| = , and = c cos Φ in the above picture? Thanks for explanation.