pool

this weekend i was playing pool and remembered that we were just talking about pool in physics. this game has a lot to do with physics in terms of momentum as well as kinetic energy. as i struck the cue ball into the other balls, force was exerted onto the other balls, however, the total momentum remained the same. This is due to the conservation of momentum. The cue ball had momentum before it hit the other balls, which were stationary and therefore had no momentum. When the balls struck each other, momentum was transferred to the other balls but the total amount remained constant. I also realized that when the balls stuck, an elastic collision was taking place. Although a very small amount of kinetic energy is lost when the balls collide, total kinetic energy is practically the same before and after the collision.

bicycle

So today I was riding erin’s bike up and down this big hill for fun, and I realized, hey this is physics! As I sat on the bike at the top of the hill, my potential energy, with respect to the ground at the bottom of the hill, was very high. I did not have any kinetic energy, or energy of motion at that moment because I was not moving. As I rode down the hill, my potential energy decreased, and my kinetic energy increased. When I finally reached the bottom of the hill, my kinetic energy was great, and but my potential energy,w ith respect to the ground at the bottom of the hill, was zero. During this ride, the total energy always remained the same. Besides the potential and kinetic energy, I could also feel the wign blowing against me as I rode down the hill. The bike’s tires were also pretty flat and I wasn’t rolling very well. This reminded me of air resistance and friction.