Friday, September 23, 2011

Unit 1 Reflection

Inertia!

On the first unit of my physics class we learned a lot about Newton's first law. Newton's first law
states that inertia is the name of the property that's states that an object in motion wants to stay in motion and an object in rest wants to stay at rest unless a net force acts upon it. It's important to remember that inertia is not the reason why objects want to keep doing what they are already doing, the reason for that is unknown and inertia is only the name of this property.
 


The video above is an example of inertia. When the tablecloth is pulled from under the dishes, they don't fall on the floor because they were at rest and for this reason they wanted to stay at rest, because there was no outside force acting on them they stayed where they were.


While talking about inertia we approach other new terms such as equilibrium and net force. Net force is when more than one force acts on an object. When the net forces are balanced and for this reason they add up to 0 Newton (measure of force) the object is said to be in equilibrium. When a body is in equilibrium it can be moving at constant speed or it can be at rest.       

Speed, Velocity and Acceleration:
After talking about inertia, we moved on to talk about speed, velocity and acceleration. We learned that speed is a measure of the magnitude of distance covered in a time period. Velocity is distance in a determined time and also takes in consideration the direction of the movement, therefore even if a car maintain the same speed in a curvy road, the velocity will not be constant. Acceleration is the rate of change in velocity over a period of time. The equations that represent those terms are:


s = d/t

v = Dd/t

a =  Dv/t

Constant acceleration:

How fast v = at

How far: d = 1/2 at2

This equations bring me to what was the hardest part of this unit. Even though the equations are straight forward, learning which one to use in each specific situation was not easy. On some of my quizzes. After some time my problem solving skills got a lot stronger because I started to understand how to use the formulas correctly. I understood the concepts of inertia and equilibrium pretty easily probably because of the hovercraft lab we did on one of our first classes. The lab helped me understand that objects in motion really do stay in motion unless there is a force acting upon it.

Conection to Real life:

This unit is extremely connected to our everyday life. Who never forgot something on top of a car and took of? Have you ever stopped to observed that the object is at the same place it was before but on the ground? This concept is explained by Newton's first law! The object was at rest and therefore wanted to stay at rest, there was no outside force to stop it from doing so therefore the object continued in the same place but on the floor. This is just one example of many situations that can be explained by inertia!