Which statement best explains why there could be a force of attraction between two electrically charged objects?'
because they have like charges
because they have unlike charges
because they have the same number of protons
because they have the same number of electrons

Select the correct answer from each drop-down menu. compared to its surroundings, the concentration of solutes is low inside a cell. so, the cell is with respect to its surroundings. a particular solute in this cell uses energy for its transport from the cell to its surroundings. this type of transport is called

Write down two additional questions about earth's magnetic field that will make your presentation more informative.

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.