What is the purpose of Rheostat in an electric circuit

The table below shows the acceleration of gravity on different bodies in the solar system. on which body would a 10 kg lamp has the most gravitational potential energy when lifted to a height of 2 m? a. earth b. mars c. neptune d. uranus

Which lists the pairs of plates in order from least to greatest in terms of the work done to move the electron?

Aforce is a vector quantity because it has both?