I have read that at high energies, electromagnetic and weak force gets stronger and strong force gets weaker and at higher energies all these forces become undistinguishable from another. But I cant wrap my head around why does this happens and why does strength of any force depend on energy? and...

Energy and force, the basic formula Can someone explain to me this chain of equalities? Namely the $v$ in the 4th term and the next term: $$\int d/dt \ ((m/2) v^2) \ dt$$ $$E = \int F \ ds = \int m a \ ds = \int m (\dot v) v \ dt = \int d/dt ((m/2) v^2) \ dt = (m/2) \ v_0^2$$

When I'm calculating the divergence of a cylinder with uniform magnetic field ($B=K=\text{constant}$) according to the formula of divergence in cylindrical coordinates I'm getting the same constant value as the divergence. $$\nabla\cdot B=K.$$ But from the physical explanation of divergence it sh...