Question

As you discussed in Activity 2.10, Relationship 2 of the Particle Model of Matter gives the relation between the force acting between two particles and the potential energy due to this force: the force is equal to the derivative of the potential energy with respect to the particle separation. The force is always in the direction that lowers the potential energy. 3) a) The electrical force between two positively charged objects is always repulsive and becomes weaker as distance increases, eventually approaching zero as separation goes to infinity. Use the relationship described above to deduce the shape of the graph of PE as a function of r over all possible separations. charges?) distance increases, eventually approaching zero as separation goes to infinity. Use the relationship b) Redo part a) for two negative charges. (What do you know about the forces between the two negative c) The electrical force between two unlike charged objects is always attractive and becomes weaker as described above to deduce the shape of the graph of PE as a function of r over all possible separations.

Answer 1

The potential energy between two charges is given by,

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Therefore for parts (a) and (b) the graph will be of the same type. Since they are like charges, the potential energy will be positive.

In part (c) the potential energy will be negative, because the charges are unlike. This gives the graph

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