Question

this photo shows a system that consists of a person on a diving board. what change could you make to the system that would decrease its total energy? a. decrease the height of the diving board. b. increase the length of the diving board. c. replace the diver with someone who has more mass. d. increase the height of the diving board.

Explanation:

Step1: Recall energy - height relation

The total mechanical energy of the system (person - diving - board) includes gravitational potential energy $U = mgh$ (where $m$ is mass, $g$ is gravitational acceleration, and $h$ is height) and elastic potential energy (if the board is bent). Decreasing height $h$ decreases gravitational potential energy.

Step2: Analyze each option

• Option A: Decreasing the height of the diving - board decreases the gravitational potential energy of the diver, thus decreasing the total energy of the system.
• Option B: Increasing the length of the diving - board does not directly affect the total energy of the system in terms of gravitational or elastic potential energy in a way that decreases the total energy.
• Option C: Replacing the diver with someone with more mass increases the gravitational potential energy ($U = mgh$), increasing the total energy.
• Option D: Increasing the height of the diving - board increases the gravitational potential energy, increasing the total energy.

Answer:

A. Decrease the height of the diving board.