On the first assessment I competed the types of energies correctly in my LOL diagram, but messed up the system by putting both the spring and cart. I found this a little confusing because in the practices from the previous week we put the cart and spring as the system, but it was different on the assessment. In addition, for my pie chart diagrams I forgot to take friction into account and I needed to add su (surroundings) to one of the charts. I also got force and energy confused, which messed up my results for the graph, but I now understand the mistake and the difference between the two. After going over it as a class question by question, I feel like I was prepared for the reassessment today and I felt pretty confident while taking it. I feel that I know the concepts much more thoroughly now.
In addition to reviewing energy, we also began exploring work and power this week. We came to a conclusion that work is a transfer of energy over a distance in the direction of the force. For example, picking up a chair and putting it over your head is work. However, setting it back down on the ground is not work because the chair is not moving in the same direction as the upward force of your hands. The force has to stay connected to the object as well, so that it is the force doing the action, not the object's inertia. Throwing a ball is not work once it is in motion because it's continuing due to its inertia.
We also worked a little bit with power, a rate of energy transfer. Power equals the work divided by the time for the work to be completed. Power is measured in horsepower or watts, but we are going to use watts for class. To calculate someone's power, you have to find their gravitational energy and divide by the amount of time it took them to complete the action. This concept is still a but hazy for me, but we will be working with it more after break.
Happy Spring Break! :)
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