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Something I learned about Physics....
During the launch portion of the motion Newton’s first and third laws are most apparent. His first law states that an object at rest will stay at rest until a (net) force is applied. The marshmallow remains at rest in the launcher’s bucket since the only force acting on it is the pull of earth and the launcher itself. Neither of these create a force strong enough to put the mallow in motion until the launching mechanism is triggered. At that time Newton’s third law comes into play. The force generated by the motion of the launcher is large enough to give the mallow motion but even so the marshmallow pushes just as hard against the launcher as it is leaving the bucket. For every action there is an equal and opposite reaction, even if the force and motion of one object causes the movement of the other. Both forces are instantaneous and perfectly equal.
During flight, the marshmallow follows an arc shaped path. This movement involves all three of Newton’s laws. In regards to the first law, there is no force acting on the marshmallow in the X direction during flight so there is no change in acceleration. There is however a change in the Y direction because of the force of the earth pulling down on the marshmallow. As the mallow travels away from the earth in the first half of the flight there is negative acceleration since it slows down from the force of the earth overcoming the force of the launcher and the mallow’s mass (2nd law) pulling it in the earth’s direction. In the second half of the flight after it has reached the top of its arc and is traveling back to the earth it has positive acceleration. This is due to the increased (net) force in the direction of the earth due to the combined force of the earth and the mallow’s mass.
During the landing phase the marshmallow goes from a state of increasing acceleration in a downward direction to a very sudden stop when it hits the ground. If in theory the marshmallow hit the ground once and stopped, it would have zero speed, velocity and acceleration. The only forces acting on it would be the force of the earth pulling down on it and the equal and opposite force of the mallow pushing down on the earth (3rd law). Since the earth’s mass is significantly larger, its’ force will continue to overcome the marshmallow’s force pushing back against it until a third force overcomes them both (2nd law).
This is a Dave Matthews parody. They are one of my favorite bands and even though the girl's guitar playing is so-so, she does talk about motion and forces and I think she even mentions Newton.
This weeks mental health update...
This week I discovered that I was way behind! I had that nagging feeling since the very first week and my worst fear was confirmed. At least I have a chance to set it all right and fix the things that didnt work. I have to say, it has been a lot of work catching up and combined with my other class and regular life, I am boardering on the breaking point. I can't tell you how glad I am that this is only 8 weeks. Granted, if this much work was spread out over 16 weeks, I probably wouldnt be so stressed.
Is dec. 21st, 2012 going to be the last day on Earth? Some say yes, some say no. Here is a video I found that offers some evidence for both sides.
This week I have had real trouble with VPython.