un péndulo oscila con un periodo de 2s y una longitud de 9m.¿que longitud debería tener para que su periodo se duplique

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?