7: Classical Physics- Gravity and Energy
- Page ID
- 30484
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Chapter 7 introduces the concepts of gravity and energy. In the first part of the chapter, you will learn that gravity, the force that causes an apple to fall from a tree, also keeps planets orbiting the Sun and is present throughout the Universe. Through the application of Newton’s Laws you will explore properties of surface gravity on other planets and the orbits of planets, stars; you will see that gravity can affect any object in space. The second part of the chapter focuses on the many forms of energy, with special attention given to kinetic energy and gravitational potential energy. You will also learn that energy is conserved. It is passed from one body to another in any interaction, but it is never created nor destroyed.
- 7.1: Gravity on Earth
- We all know that we are held to the ground (or floor or our chair) by some physical effect. We can jump off the ground, but we do not rise very far before we reverse direction and fall back down again. We also know that if we step off a high cliff, we will fall. Our downward speed will increase as we fall until some object obstructs our motion. Why is this the case?
- 7.5: Forms of Energy
- In this section, we will look at the concept of energy in some detail. Ideas related to energy will bolster our understanding of how and what changes can occur in the Universe and the objects it contains. The two kinds of energy that we will focus on here will be gravitational potential energy and kinetic energy. We will describe potential energy first.