# 23.3 Potential Energy Reference State | Summary and Q&A

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June 2, 2017
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23.3 Potential Energy Reference State

## TL;DR

Potential energy is calculated based on the difference between an initial and final state, and the concept of a reference point is introduced to simplify calculations.

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### Q: How is potential energy calculated in a gravitational problem?

Potential energy in a gravitational problem is calculated by finding the change in potential energy between initial and final heights, using the formula mg (y final - y initial).

### Q: How does introducing a reference point simplify potential energy calculations?

Introducing a reference point allows us to measure potential energy differences between any state and the reference point, making calculations easier.

### Q: What is the potential energy function for the gravitational force?

The potential energy function for the gravitational force is U(y) = mg y, where U(0) = 0 since we choose the reference point at the origin.

### Q: Why is it important to have a reference point for potential energy calculations?

Having a reference point allows us to determine the potential energy difference between any state and the reference point, making it easier to analyze and compare different states.

## Summary & Key Takeaways

• Potential energy in a gravitational problem can be calculated by finding the change in potential energy between initial and final heights.

• Introducing a reference point allows us to measure potential energy differences between any state and the reference point.

• By choosing the reference point at the origin, the potential energy function for gravitational force becomes U(y) = mg y.