A pair of two equal and opposite electic charges

the work done per unit charge by an external agent in bringing a small point positive charge from infinity to a point

the work that needs to be done by an external agent in order to bring a set of charges from where they were separated by infinite distance to their current position

set of points that have the same potential

the minimum speed at launch so that a particle can move to infinity and never return

the work done per unit mass by an external agent in bringing a small point mass from infinity to a point

the work that must be performed by an external agent to raise a mass to a certain height from a position where the height is zero, or to bing a set of masses to their current position from when they were separated by an infinite distance

two parallel and equally but oppositely charged plates

the distance from the centre of a star where the escape speed is the speed of light