Tuesday, January 26, 2010

Circular Motion and Gravitation

This is what I learned about Circular Motion and Gravitation. I learned that when moving in a circle, an object travels at a distance around the perimeter of the circle so that when the car moves at 5 m/s, the car would travel 5 meters along the perimeter in one second. This is the period T to get one complete rotation and it is given in seconds. The frequency is the number of rotations per second. In the case of circular motion when an object is accelerating, the acceleration is centripetal, meaning towards the center of the circle. I have also learned about Newton's Law of Universal Gravitation, which states every object is attracted to every other object in the universe.

What I have found difficult about what I have studied is figuring out what the centripetal force is. At first, I had no idea how to find it but now I realize the Centripetal force is the force pointing towards the center of the circle in the FBD. The Centripetal force is provided by the force which keeps the object in circular motion.  I have also found it difficult when the coefficient of friction is added to the problems. I did not know where the equation of mu times mg was from but then I learned where it was made from and how to convert it into my problems.

My problem solving skills are growing. With each mistake, I see how to apply every equation to solve any problem. I am doing well with the FBD's and knowing what provides the centripetal force. An area of concern is I am not sure what exactly the force to maintain the car's circular motion is. But for now, my problem solving skills are fine.


  1. Good reflection! Please clarify what you said: "the Centripetal force is the force pointing towards the center of the circle", do you mean that this is a special kind of force or is it provided by other force?

  2. Thank you I have cleared that up now

  3. Hi Jonathan! My name is Maggie and I'm a junior at JPII.

    This is a really good reflection. I had some trouble with the coefficient of friction too, but it's good that you got it figured out! One thing is, with the Newton's Law of Universal Gravitation, you just gave the definition, but didn't explain it. How are the objects attracted to each other? Also I think it's great that you are doing well with the free body diagrams because I know that for me, at least, it really helps to have a way to visualize what you're working out. Good job, it sounds like you are doing well! :)