Energy: What Makes Life...Life.

For our reflections on our unit over energy, we were required to think of a real life situation that was related to what we were studying. For my topic, I chose football. Instead of just recollecting what we learned and what we didn't, this required us to critically think about the lesson in real life, not just scenarios made in the class room.



Attributions for my images:
http://www.statefansnation.com/wp-content/uploads/2009/06/football.jpg
http://cdn2.sbnation.com/imported_assets/406750/football_spinning.gif
http://www.webweaver.nu/clipart/sports-football.shtml
http://www.scasd.org/25452078145137270/lib/25452078145137270/football_ref_touchdown_hclear.gif

Mythbusters: Physics In Action

For our latest experiment, we duplicated what would be an episode from the famous Discovery Channel show, Mythbusters, in our own way. We were given two "myths" that had to do with physics in action and we had to do what we could to prove or disprove them. 

MYTH #1:

An object always moves in the direction of the net force exerted on it.

At first glance, this may seem obvious: yes. However, it's possible for this to be proven wrong if looked at very closely. We predicted that if and object doesn't always move in the direction of the net force exerted on it. If this were true and you were to push an object on wheels in a certain direction, then as soon as you stopped pushing, the friction being the only net force after the applied force is taken away would cause the object to go in the completely opposite direction instantaneously. To conduct our experiment, we used what we  called a "mancoaster". We put one of us on said coaster and another team member pushed the coaster. Here is our free body diagram of the situation after the applied force is no longer present. 

ΣF = Ff because ΣFy = Fn - Fg and when they both equal each other they cancel out, therefore the net force is just the force of friction. With this being true, we busted the myth by proving that even though the net force on the coaster is in one direction the mancoaster continues to move until it comes to a stop, but never does it actually move in the direction of the net force.

MYTH #2:

An object always changes its motion if there is a force exerted on it by other objects.

If an object were to always change its motion due to any force exerted on it by other objects and we were to roll a bowling ball and hit it with a small highlighter, then the bowling ball's motion would change. However, we predicted that this myth is NOT true, and that if we were to perform this experiment that the bowling ball's motion would not change. Our experiment was simple: we took a bowling ball so kindly supplied to us by Mrs. Gende and found a hall in which we could roll it. We proceeded to roll it and closely examined it to see what would happen to it if we were to throw a highlighter at the rolling ball. Here is a free body diagram at the exact moment that the highlighter hit the bowling ball.

Our experiment busts the myth for the reason that despite the fact the highlighter hit the ball while it was rolling (quite hard, might I add) the ball did not stop rolling or change direction. It would take a three dimensional FBD to truly show the highlighter hitting the ball, but nonetheless, the ball was not affected.

Conclusion

The two myths at first seemed like they'd be easy to prove as true, but by actually sitting down and reading them carefully and fully thinking of every possibility, we realized we could easily disprove them. Some could debate on the busting of the second myth because they could say that the ball "slowed down a little bit" or that it "ever so slightly changed its course". Regardless, this doesn't make these myths true. It just means the way we decided to disprove it isn't "100% correct" according to some.

People believe these myths in the first place because they do not look deeper into the possibilities. One could be a leaf hitting a bird in flight. Unless the bird freaks out, it will most likely keep flying in the same direction. This is beside the point though, it just shows how some people just wouldn't see the deeper possibilities. As for the first myth, people believe in this often because if one was to simply look at an object in motion, they only see the net force that was used to put it into motion, not the forces acting on it in the air or one the ground, such as air resistance or friction.

Once again, bye for now Physics World.