Okay, so I know physics isn't everyone's favorite thing to talk about, but, being teenagers, and driving and all, you kind of wonder how things move. Newton has three laws of motion to explain how things move. (Maximize your browser for best viewing efficiency.)



"I am Sir Isaac Newton, the funkiest dude on Earth."

Newton's First Law of Motion: Every body contains in its state of rest or of uniform speed in a straight line unless acted on by a non-zero net force. The tendency of a body to maintain its straight of rest or of uniform motion in a straight line is called inertia. As a result, Newton's first law is often called the law of inertia.


Newton's Second Law of Motion: The acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to its mass. The direction of the acceleration is in the direction of the net force acting on the object. The familiar statement of Newton's Second Law is åF=ma. The a stands for acceleration, m for mass, and åF for the net force. (If anybody is going, "What is net force?!?", it's the vector sum of all forces acting on the body. FYI: The å is supposed to represent the Greek letter for sigma, which means "the sum of". It comes up wrong on the computer.)

Newton's Third Law of Motion: Whenever one object exerts a force on a second object, the second exerts an equal and opposite force on the first. For every action, there's an equal and opposite reaction.

Let's apply our new-found knowledge to real life!!!!
Alright, who's watched the winter Olympics?

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"Ooh ooh ooh, ME! ME! I've watched the winter Olympics!!"

When watching the bobsled people do their stuff, you notice that they give a big push to keep going throughout the course, and they have to give enough force so that they go fast or otherwise, they'll lose big time and won't go gold. This is Newton's second law in motion. (Remember kids, if you don't remember what Newton's Second Law is, LEARN IT, or you could just go look up at the top of the page...) Or, for those of us who are crazy and wild drivers who run out of gas or get stuck in mud, you have to use force to push the car out of its stuckageness. You could apply Newton's First Law to this sticky-stuck situation. Or, if you're one of those bullies who beats up on people, you could remember that for every action, there is an equal and opposite reaction....

Here's a problem that uses the slope of the height and kinetic energy to find the force. It shows you how the force increases with more energy.

A 1200.0 N sled is pulled along a horizontal surface at uniform speed by means of a rope that makes an angle of 30.00 degrees above the horizontal. If the tension in the rope is 100.0 N, what is the coefficient of kinetic friction?


Here's how you do the problem:

To find the normal force, take 1200.0 N minus 100.0 N, which is the tension of the rope. The answer is 1100.0 N.

To find y, draw an imaginary triangle off of the rope and use the Law of Sines to find that y equals 50.0 N.

To find x, plug in the degree of the angle and the radius, which is 100.0 N. X equals 86.6 N.

The sum of the forces equals the force of acceleration minus the force of friction. (The force of friction equals the coefficient of friction times the normal force.)

Start plugging in what you know. You know the force of acceleration is 86.6, because that's where the object is going. Y plus the normal force equals 1150.0 N. The sum of all the forces will even each other out to equal zero, so now just solve for the coefficient of friction. This will equal 0.0753 N.

Links to other sites
How Do Newton's Laws of Motion Apply to Space...
Laws of Motion
Newton's Laws of Motion
Sci 122:Newton's Laws
Motion
Laws of Motion
Applications of Newton's Laws

These sites are all related to the topic of the webpage (somehow..). Visit them and I think you'll find that they're prettty cool.

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I am Jennifer Hui, a senior in the Advanced Placement Physics B course at Fayetteville High School in Fayetteville, Arkansas. (Mr. Young, you're going to love this part): My uncle is a physics professor at the University of Arkansas. His daughter's boyfriend (aka my cousin's boyfriend) is a screenwriter/actor (rent Leprechaun 3 and see him as the star!!) His latest screenplay called Varsity Blues is currently being filmed. It stars James Van Der Beek, aka Dawson on the popular TV show Dawson's Creek. This has everything to do with physics -- just remember my uncle's daughter's boyfriend!

This page is a required element in one of my portfolios, which are due every nine weeks. I had to choose a topic related to physics and which I enjoy, so I chose Newton's Laws of Motion. These, to me, seem to exemplify what physics embodies. It's something so crucial to physics, and you have to learn it. If you don't get it, YOU'RE SCREWED FOR PHYSICS!! You can email me at dede24462@aol.com if you have any questions, or if you think I'm pretty cool for doing this..but if you hate it, I don't want to hear it. If you want to talk to my physics teacher, email him at dayoung@ecs1.nwsc.k12.ar.us.


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