Tuesday, January 26, 2010

Reflection: "Circular Motion and Gravitation"

I learned about circular motion, gravitation, and centripetal force. We learned before the difference between scalar and vector quantities, which comes in handy when it comes to centripetal force. Objects moving in a circular motion have a constant speed, but that doesn't mean the velocity will be constant since the object is changing direction. An object traveling at a constant speed in a circular motion is said to be in uniform circular motion. In order to obtain the velocity (m/s), one must figure out the distance and the period. To find the distance (around a circle's perimeter), you would use the equation: 2∏r. "T", the period, is the time that it takes to complete a full rotation. Also, an object is considered accelerating if it is changing direction. In circular motion, it's called centripetal acceleration. Acceleration is perpendicular to the velocity. Also, the inward force that keeps the object in a circular motion is known as the centripetal force. Moving on to universal gravitation, the Law of Universal Gravitation states, "Every object in the universe attracts every other object in the universe with a force that varies directly with the product of their masses and inversely with the square of the distance between the centers of the two masses." There is a lot to know about circular motion and gravitation!

What I have found difficult is drawing FBDs for objects in circular motion. I get confused as to where to place the arrow that describes where the acceleration is going. Also, I sometimes have finger problems when typing universal gravitation equations into my calculator. I believe that these difficulties can be solved over a short amount of time though.

I feel that my problem-solving skills are average. I definitely think that there is room for improvement though! On problems that aren't exactly like ones I have done before, I need to use similar skills used on previous problems rather than freaking out because I haven't seen anything like it. I feel that I am fairly good at figuring out the data I have and the data that I need to find out though. With some more practice, I can get my problem-solving skills to above average!


  1. Excellent reflection! I particularly liked how you stressed the importance of differentiating vectors from scalars.

  2. Excellent job with circular motion, but your gravitation explanation seems to be just a quote. You might want to add a little of your own explanation. Gravitaion is a tricky topic and you want to be sure you understand it completly. But again, great job with circular motion.