UNIT 8!

Last unit of the quarter!
So today we learned about work and different types of energy!
Work is any change in energy so it can also be written as delta E, or W. Work is force times distance and the Sum of energy in is equal to the sum of energy out! The Law of Conservation of Energy is that energy cannot be created nor destroyed, its form can only be changed. So work equals N x M, or units in Joules (J).
We learned about Potential (Gravitational) Energy=PEg=Ug. So delta E=W=F•d=mg•h.
and

Kinetic Energy which is written KE=K=1/2mv^2.
SO there are two examples we used to show where potential and kinetic energy occurs. Firstly the pendulum! I decided to recreate this at home by connecting a broken hand fan (the ones powered by a battery) and taping it to the door frame. I let it go and didn't add any force to it. If the world were a perfect place, it would return to the exact same spot at which it was dropped and go on forever, but no. Since there was frictional forces between the string and the attachment to the door and energy going to friction takes work out, it wouldn't return the same spot. It began with potential energy, but then as it reached the equilibrium point (low pt.) it had kinetic energy, then potential, then returned in the opposite direction with kinetic energy, then ended in potential energy. If it was pushed, I'd be adding energy to it. So it would be potential energy and work together!

The other example we used was dropping an object from a high area. In class we used a bar for example and it was at 100 J, halfway it would be 50J potentional energy, and 50J kinetic energy, then at the bottom of the fall right before landing it would be at 100J kinetic energy. So it would start off with 100J and end up with 100J of energy, proving that Ein=Eout. If for example my shoe had a mass of 2.2kg and fell from a height of 3 m. My energy would be PE=66J, PE=33J/KE=33J, then before it lands it would be at 66J.