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nathanstack15 last won the day on December 17 2016

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About nathanstack15

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  1. Physics of Equilibrium

    I recently saw this picture on one of my friend's Snapchat stories. How is this water bottle able to balance on its side? The bottle is positioned so that its net torque is equal to zero. On the left side of the bottle, the force of gravity due to all of the infinitesimally small pieces of its mass on one side of the system's center of mass multiplied by the distance that their weight vectors are from the center of mass (AKA the counter clockwise torque) has some definite magnitude. On the right side of the bottle, the forces of gravity due to all of the tiny pieces of mass multiplied by their distances from the center of mass equals a net clockwise torque on the bottle. The counter clockwise torque and clockwise torques applied to the bottle are equal in magnitude and opposite in direction, causing the bottle to remain in rotational equilibrium. The calculus behind this situation is quite complicated, as you can probably tell.
  2. You didn't spell sledding right
  3. I always thought that bullet proof glass was made of a special type of glass that could absorb the kinetic energy of a bullet without shattering. That's very interesting, that bullet proof glass is really a combination of both glass and plastic.
  4. Physics of Hip Checking

    This past weekend, I went to an IHS hockey game, and noticed that @SJamison was able to completely send his opponents off of their feet without even applying too great a force to the opponent. Skylor continually used the hip check, which seemed effortless compared to body checking and a lot less painful for the defender. What is the physics behind hip checking? By applying a force further from a player's center of gravity, a defender applies a torque to the other player, causing that player to experience a rotational acceleration which makes it easy for that player to lose his/her balance. The defender's hip does not need to apply a force other than letting the offender skate into their hip basically. By causing a rotational acceleration of any magnitude, an offender can easily lose their balance. Body checking is much more difficult, however, because in order to stop a player's momentum, the defender needs to have a momentum at least equal in magnitude and opposite in direction.
  5. Is it better to hit someone straight on in hockey or to hit them at their hips so that they experience a rotational acceleration?
  6. That's crazy that only 35 Nm of torque can snap your UCL
  7. No matter what happens in an action movie, the main character never gets hurt, no matter how crazy he stunt he tries to pull.
  8. This past week in physics, we learned about Gauss's Law for electricity. It states that the electric flux, or the amount of electric field penetrating a surface, is proportional to the charge enclosed within the surface. Interestingly, Gauss's Law does not only apply to electricity: it also applies to gravity. According to Wikipedia, gravitational flux is a surface integral of the gravitational field over a closed surface. This is analogous to electric flux, equivalent to the surface integral of the electric field over a closed surface. Gauss's Law for gravity is mathematically represented by this equation: {\displaystyle \scriptstyle \partial V} {\displaystyle \mathbf {g} \cdot d\mathbf {A} =-4\pi GM} , where represents a surface integral over a closed surface. Gauss's Law for electric fields states that: = {\displaystyle \scriptstyle _{S}} {\displaystyle \mathbf {E} \cdot \mathrm {d} \mathbf {A} } . Electric flux can also be represented by 4 pi k Q. Since G is the gravitational constant analogous to k for electricity, and since M is analogous to charge, it makes sense that total gravitational flux is equivalent to -4 pi GM. Gravitational flux is negative because gravitation fields always attract, where electric flux can be positive or negative depending on the enclosed charge.
  9. This past week in Physics C, we started the electricity and magnetism course. It has proven to be very difficult so far, especially when talking about electric fields and finding electric fields at a point by integrating across an object where its charge is uniformly distributed. I am even more scared to start learning about Gauss' Law. Since I do not entirely understand the hard stuff yet, I'll talk about simple electrostatics which can be seen in everyday circumstances. Charging by conduction, for example, occurs when materials become electrically charged by contact. This can be seen by rubbing a balloon against your hair. The atoms in your hair lose their valence electrons, which are transferred to the balloon, leaving your hair positively charged and the balloon negatively charged. If you place the charged balloon to the wall, it will stick because the wall is more positively charged than the balloon, and since opposite charges attract, the balloon sticks to the wall.
  10. Yeah Paul is garbage man, you should get a better team mate. I can't remember the last time that David and I lost
  11. I wonder how elastic the collision between a ping pong ball and a ping pong paddle is. Some of the energy must be converted to sound energy, and some energy must be lost due to friction.
  12. I wonder how much of the original potential energy when the roller coaster is at its highest point is lost due to friction. Also, doesn't air resistance do work on the roller coaster, changing its energy as a system?
  13. Today was an unfortunate day in Physics class. After some bickering over some physics problem between my brother Jason and I, we decided that the only way to properly settle our dispute was to arm wrestle. Unfortunately, he beat me. Although I did not get the victory I deserved, I noticed that arm wrestling has quite a lot of physics to it. When arm wrestling, both people are trying to apply a greater torque than applied by the other person. Since torque equals the force applied times the distance from the point of rotation, the greater the arm length, the greater the applied torque. However, arm length plays a very small factor in terms of who has the advantage in an arm wrestle. According to, "Stance, muscle density, stabilizer muscles, shoulder muscles, as well as where the specific tendons and muscle fibers attach to the bone are more important, and play a much larger role in arm wrestling. These same attributes are the reason why primates are generally much stronger than humans despite their smaller stature and size." In my opinion, Jason is not the true arm wrestling champion until he beats a primate. You've got a lot of work ahead of you @jcstack6
  14. Physics of Trampolines

    This coming Friday, I'm going to Skyzone with a bunch of my friends. If you've never been to Skyzone, an indoor trampoline park, you definitely should go. I've been thinking about the ways that trampolines work, and notice that they demonstrate an important physical concept: conservation of mechanical energy. When jumping on a trampoline, your weight and work done by your legs causes the elastic surface of the trampoline to stretch and it causes the springs attached to the trampoline to stretch. The springs and surface of the trampoline eventually stretch until the velocity of the person is 0 m/s. This is the point at which the springs and surface are at their amplitude. Since spring potential energy equals 1/2 k x^2, the greater the amplitude or maximum displacement from equilibrium, the greater the spring potential energy in the system. Since mechanical energy is conserved, the spring potential energy when the springs and surface of the trampoline are at their amplitude must equal the gravitational potential energy when the person jumping is at their maximum height. Therefore, the more work that your legs do in stretching the surface and springs of the trampolines, the greater their amplitude will be, causing the spring potential energy to be greater, causing the maximum height that you reach to be greater.
  15. Physics in The Simpsons

    The other day, I was watching The Simpsons, one of my favorite TV shows, and noticed that in a particular scene, one of the characters, Mr. Burns, experienced multiple laws of physics in action. He was on a camping trip with his millionaire friends, and, with a shotgun, attempted to shoot a stationary pigeon. Mr Burns, who is unrealistically underweight, shot backwards dramatically after firing the gun. This occurrence demonstrates conservation of linear momentum. Originally, both him and the gun were stationary. After firing the gun, the bullet of relatively little mass travelled at an extremely high velocity in the positive direction. Since linear momentum is conserved, Mr. Burns' body was propelled in the negative direction at a high velocity because of how small the mass of his body is. Therefore, the mass of the bullet times its velocity minus the mass of Mr. Burns times his velocity is equal to 0. Mr Burns was, unfortunately, standing next to a lake, and was propelled into it. However, he did not sink in the lake. This occurred because of the surface tension of the water. The force of gravity on Mr burns is relatively small, considering how little he weighs. When he came in contact with the water, the surface tension of the water was greater than his weight, causing him not to accelerate into the water.