september+24,+2008

September 24, 2008 Kelsey Carr-Gardner

Today in physic class we went over the homework. Which explained why we feel like were being pulled forward in a car as it slows down, or why feel as if we are being pushed back as it starts. It all has do do with inertia and where are body is in that place and time. Newton's law of inertia states that a body at rest wishes to say at rest, and a body in motion wishes to stay in motion. We also covered the reason why one can throw a ball upwards and catch it while inside a moving airplane. Its because the ball is traveling at the same speed the airplane is, as the plan is traveling in a straight line or stopped. After we went over the homework we discussed the four types of forces: After a quick review we broke in to groups and did a short lab. In the experiment we had a weight set, lab cart, a rubber band, and a ruler. We were trying to figure out what type of force it would take to to cause the cart increase speed. So we hooked the rubber band to a weight and started to increase the acceleration. We figured out that if you increase the force then the speed would increase as a result. To keep the cart at a constant speed we had to apply a constant force, which took about .6 Newtons.
 * normal-a pressing force, like standing and leaning on a wall
 * tension- caused by stretching, like your on the monkey bars
 * friction- which is caused by rubbing, like rubbing your hands together keep them warm
 * gravity- is any two objects that have mass attract to each other, like an apple falling to the earth