Science

Up to this point we have learned to solve problems with force vectors and the kinematic equations to analyze the motion of objects, and we saw that some forces can cause rotation. All of these quantities are vectors, and require an analysis that uses vectors. Energy analysis is a competing method to forces that can give you the same information, but doesn't involve vectors.

Work and Energy

If a net force acts on an object and causes it to move, we say that those forces did work on the object to displace it. Work is a measure of effort by a force. To compute the work done, we simply multiply the force and the displacement; however, some forces can't do work because they don't contribute to the displacement. Therefore, we only need to use the component of the force that causes the displacement. In Module 1, we learned that we can break vectors into components using sine and cosine. To find the component of the force that causes displacement, we need to find the component of the force that is on the same axis as the displacement. We often refer to this as the parallel component of the force

$$W=\mathbf{F}\mathbf{·}\mathbf{d}=F_{||}d=Fd\cos \theta$$

In this lecture we will introduce work and its relationship to forces.

Time: 6:29

 

Work-Energy Theorem, Potential Energy, and Non-Conservative Forces

In this lecture we will cover the Work-Kinetic energy theorem, compare the work done by conservative vs non-conservative forces, and then look at some energy diagrams

Time: 9:36

Total Energy & Energy Conservation

In this video I will summarize the major topics from this lesson, and as a bonus I have something for you to think about. Additionally, the answers the questions about the simple machine are given.

Time: 8: 56

 

Key Lessons and Appendix 

This video is a summary of the videos in this module.

Time: 9:00