Dos cargas idénticas, están a una distancia de 15cm y la fuerza de repulsión entre ambas es de 40N.¿ a cuanto vale la magnitud de cada una de las cargas ?

Anybody wanna ? (picture included? )

What happens when the vapor pressure of a liquid is equal to the external pressure?

You want to move a heavy box with mass 30.0 kg across a carpeted floor. you pull hard on one of the edges of the box at an angle 30∘ above the horizontal with a force of magnitude 240 n, causing the box to move horizontally. the force of friction between the moving box and the floor has magnitude 41.5 n . what is the box's acceleration just after it begins to move