Unit 5 Reflection

This unit in Physics we learned about work, power, potential energy, kinetic energy, and machines. Beginning with work, we learned that work = force X distance. But, this is only so when the force and distance are parallel and not perpendicular to each other. Work is measured in the unit of joules. After learning about work, we learned about power. Power = work / time. Power is essentially how quickly one is getting work done. Power is measured in watts. 746 watts is equal to one horsepower. We commonly hear the work horsepower used when talking about cars, specifically the power of their engines. Cars with a big horsepower can go faster quicker because their engines do work faster. Next, we moved on to Potential Energy. PE is energy stored and held in readiness. It is called “potential” energy because it is in a state where it has potential to do work. An objects PE is determined solely on its position. To calculate an objects PE one can use the Formula, PE = (mass)(gravity)(height). Moving on, we learned that Kinetic Energy is energy in motion. KE is dependant on an objects mass and speed. KE = 1/2mv^2. The change in KE is equal to the KE final – the KE initial. Or, the change in KE is also equal to work. If an objects speed is doubled, the KE is quadrupled. When learning about energy, it was important to know that law of Conservation of Energy. This law states that, “energy cannot be created or destroyed; it may be transformed from one form into another but the total amount of energy never changes” Post energy, we began to study the use of machines. For example, the ramp is a simple machine. Machines make doing work easier. Take the ramp for example. The ramp is going to increase the distance in which you are doing work allowing you to use less force. We know this because we know that the amount of work that you put into a machine is going to equal the same amount of work that you are going to get out. Work in = work out If you put a certain force with a certain distance in a you ultimately increase the distance with a machine your force needs to be lower in for to be equal to the previous work. Fd=fD. While machines are useful, they are never 100% efficient. Some energy will always be transferred through various things such as heat due to friction, motion or vibrations, light, or even sound.

This unit I found to be fun. Work and power were both things that I was somewhat familiar with and both were easy to relate to the real world. This unit I found myself misunderstanding some questions on the quizzes, which was 100% avoidable. I could benefit from asking questions if I need clarification during a quiz. Otherwise I feel like this unit went well for me.