Sunday, January 10, 2010

Newton's Second Law

Part A:

I learned about Newton's Second Law about acceleration and forces. Newton stated that "for a particular force, the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object." In an equation, this would be a=∑F/m, which could also be seen as ∑F=ma. Newton's Second Law provides a concrete connection between force and acceleration. Also, the directions of acceleration and the force are the same. Also, in this unit, we worked with friction a lot. In order to get the net force used in Newton's Second Law, we sometimes need to know friction. There are two types of friction, static and kinetic. Static friction occurs when objects are at rest, and kinetic friction occurs when an object is in motion. With this information, it was possible to solve problems pertaining to forces and acceleration.

What I have found difficult is knowing what equation to use. I find it challenging to set up an equation sometimes because it confuses me on when to set the equation to equal zero or m×a. Once I figure out the correct equation, though, I can solve the problem without much confusion.

I feel that my problem-solving skills are accurate enough to succeed in honors physics. In other words, my problem-solving skills are average. As mentioned in reflection 1, I sometimes get impatient and frustrated when I can't figure out how to solve a problem. I do, however, feel confident in drawing FBDs and solving for the unknown once I have figured out the equation to use. My weaknesses include occasionally forgetting to multiply the mass by 9.8 in order to get the weight of an object, or visa-versa. I do feel, though, that I can solve the majority of problems without a hitch.


  1. Excellent reflection! Can you add something about situations that involve friction?

  2. Great work but I would recommend to go deeper into the connection to our all-day life.

  3. Thanks, Julius! But, what do you mean "all-day life"...did we have to do the application part?

  4. This is a good reflection, you seem to have to basic principles down pretty well. One thing you should note (I don't know if you have learned this yet) is that there is a third kind of friction, rolling friction. Also, a tip for solving force problems - you should always set force equal to mass times acceleration. If a=0, f will =0, and this will always at least give you a place to start.