Recent content by sea333

I am mainly looking for some modern book with media links in the book.

so you can't recommend to your students any English books?

If you are a high-school teacher can't you recommend a few books?

Is there a good "classic" book available?

Can you recommend introductory physics book for high school that contains E & M ? It should not have any integrals.

1 - cos^2(10) + sin^2(10) = 2sin^10 because cos^2(10) + sin^2(10) = 1

I have checked this and I get r = 2a*sin10

I don't think I will need these advance techniques in my exercises

sqrt(4a^2sin^2(10)) = 2*a*sin10 How do you get from 1 - cos^2(10) - sin^2(10) to 2 sin^2(10) ?

I still don't see how this is correct as angle 10 is not adjacent to r

correct solution

It looks like the Tan approach was correct

When I changed the sign now result looks correct. I don't think you can get r in such a way because angle 10 degrees is not adjacent to r

This looks easy, but why was my attempt flawed with Tan10 ?

q*q/(4*PI*Eps0*r^2) = (m*g / Cos10) * Sin10 And then just move everything except q on the right side