Monday, December 7, 2009

Part A:
This is what i learned about Newton's first law of motion. Newton's first law states that "an object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force." This law pertains to translational equilibrium. This means that the sum of the forces on the x axis and the sum of the forces on the y axis add up to zero. If the object is at rest or at a constant speed than it is at translational equilibrium. This simple knowledge helps to solve many problems, with the help of a little algebra. To solve these problems i learned how to draw free body diagrams (FBDs). These diagrams show all the different forces acting on an object and help me better understand the problem and what it is asking. I have also learned about rotational equilibrium. This has to do with rotations and torque. It adds the sum of the torque forces to the problems. The sum of the torque forces also add up to zero when it is in rotational equilibrium.

What i have found difficult about what we are studying is when the objet is on an inclined plane. This gives me trouble, especially when i have to switch the SIN and COS on theta. Also, the algebra sometimes gives me a little difficulty, especially when i do not take my time. I tend to be over- confident in the algebra, and go way too fast. I make small mistakes which ultimately lead to me getting a totally wrong answer. Last, the rotational equilibrium confuses me greatly. I am still new to this topic, and still do not fully understand the concept. The FBDs are fairly easy but finding the answer is still a bit confusing to me. 

My problem solving skills are pretty good i would say. I think they could be a lot better if I would slow down and take problems one step at a time. I think if I would look over my equations before i try to solve problems, that would help me not to confuse them. I also think that if I checked over my work more I could catch small careless mistakes. Also, I believe if I would do a few more problems over the concepts that confuse me more often that i would grasp the overall concept better and be able to solve more problems. Overall, my problem solving skills are pretty good, but i have a few small issues with solving problems sometimes. 

Part B:
There is a big connection between Newton's first law and everyday life. This law and forces are found everywhere! For example, a bridge over a body of water has to have beams to keep it up. These beams have to be able to withstand so much force, and that can be determined by this law. If the beams could hold up the bridge but not he cars, then the bridge would fall and many people would die. Second, a stoplight i s a great example of tension. The wires holding the light up have to be strong enough to hold up the light and not fall or break. If we did not know how to calculate these things, many bad things could happen. Physics and Newton's first law ( Translational and Rotational equilibriums) help not only architects, scientists, designers, and inventors; but they help everyone!


  1. Great job, Kellye! I like how you were to the point and specific when using real life examples, as well as your description of Newton's First Law. Also, I agree with you about switching COS and SIN for theta sometimes...that can be tricky.

  2. This looks great! I think you will learn to calculate the friction force very quickly. I also agree that this unit helps you understand and draw FBD's because most problems require it as part of the answer and that it helps a lot while solving problems to see if you count a force as positive or negative in your equation. GREAT WORK!!!

  3. Thanks eric! I think you commented on the wrong one... haha but thanks! and and i know if my FBD is messed up i get the whole problem wrong haha!