Question

a balloon is given an electric charge by rubbing it on a sweater. then its placed on a wall, and it sticks to the wall. the balloon experiences forces due to interactions with other objects, as modeled below. which of these interactions store potential energy? choose 2 answers: a the frictional interaction between the balloon and the wall b the normal interaction between the balloon and the wall c the gravitational interaction between the balloon and the earth d the electric interaction between the balloon and the wall

Explanation:

• Option A (Frictional Interaction): Friction is a non - conservative force, and frictional interactions do not store potential energy. Energy is dissipated as heat in frictional interactions.
• Option B (Normal Interaction): The normal force is a contact force that arises from the deformation of objects. Normal interactions do not store potential energy in the way that gravitational or electric interactions do.
• Option C (Gravitational Interaction): Gravitational potential energy is stored in the gravitational interaction between two objects (here, the balloon and the Earth) based on their relative position (height). The formula for gravitational potential energy is $U = mgh$ (where $m$ is mass, $g$ is acceleration due to gravity, and $h$ is height), which shows that the gravitational interaction stores potential energy.
• Option D (Electric Interaction): Electric potential energy is stored in the electric interaction between two charged (or polarizable) objects (the balloon and the wall). The electric force between them depends on their separation and charge, and this interaction can store potential energy.

Answer:

C. the gravitational interaction between the balloon and the Earth
D. the electric interaction between the balloon and the wall