1) kinetic energy, which is associated with motion and mass,
2) potential energy, which is associated with position!
Some of the language used in the homework problems is perplexing, (e.g., the work done on something, the work-energy theorem... ). Don't worry to much about the words and superficial linguistic conventions. Most of the problems can be solved using conservation of energy concepts, as we will discuss on Wednesday.
PS. let me know if the deduction for tries is still too high and we can try to change it.
How would you go about doing problems 8 and 9, where angles are a factor?
ReplyDeleteGood questions, and really good point about problem 8, Shelby!
DeleteFor problem 9, first imagine the pendulum string is straight down. Then the ball is directly below the center of the circle (the attachment point of the pendulum). On the other hand, if you pull the ball like 45 degrees to the side, then the ball is off to the right by .71 r, and also below the center of the circle by .71 r.
So then I think it is about .29 r higher than it was. Does that make sense?
Take it from there. Try drawing some pictures, and maybe you can figure out how high the ball is for the angle given to you in the problem. (I think the angle is random and different for each student..)