waikiki

I was at waikiki this weekend and as I was taking pictures of people walking on the street I noticed that the image of the cars looked really interesting. It's kind of dark so only the lights are really noticeable. Since the cars were in motion, they had kinetic energy (.5mvsquared), and since they were probably accelerating (change in velocity or direction), they also had work (change in kinetic energy) and power (change in work over time). The motor in the car is doing the work to make the car accelerate and gain kinetic energy. Even a simple thing like a car driving involves the majority of the lessons we have learned so far. If there was a collision (although I wouldn't hope to see one) then that would have involved the latest chapter we covered. I seem to notice physics in places where there are cars...

trash cans and newton

I was in Moanalua Gardens today and as I was walking in I noticed a trash canbeing held up by rocks. I don't really know why it needed rocks to support it, but I do know that there is some physics involved. The weight (massxgravity) of the trashcan and the rocks is being balanced by the normal force of the ground. The weight of the trashcan is also pushing against the rocks, which are also pushing it back because for every force there is an equal and opposite one. The forces are balanced because the trashcan and rocks are at rest. There is also only vertical forces acting upon the trashcan and rocks. Although it is strange to have a trashcan sitting on rocks, at least there's some physics involved!

Tension in the air

My mom just bought some poupouri for her car and as I was filling the little pouch with all of the beads, I was reminded of tension. As I was tugging the pouch shut, I was exerting a force on the string that added to the tension in it. The combined vertical tension of the two strings was equal to the weight (massxgravity) of the pouch and the horizontal tension of the strings going in opposite directions were equal to each other once the pouch was pulled shut. However, while I was pulling the strings, the left side seemed longer than the right side, which I think means that I pulled with more force with my left hand than my right. But then, time is used for power, so maybe my left hand used more power?