torque

this weekend i went to the mall. it was super crowded, and i was forced to park in a very tight space. While turning my steering wheel left and right as i maneuvered into the stall i noticed that every time i turned the wheel, physics was taking place!! I remembered the lesson i had learned the day before about torque. Torque causes my wheel to change its state of rotation and allows me to steer the car. By turning the steering wheel, the torque caused angular acceleration, or a change in angular velocity. The equation for torque is torque=(force)(lever arm). The lever arm is the distance from the axis to the force. In this case, the axis is the middle of the steering wheel near the toyota symbol, and the force is my hand. Physics is great!!!

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.

Physics class!!!

This picture best describes the way I feel about physics right now. I feel like a little kid trying to sumo wrestle a 400 pound man. The big guy represents physics. I feel overwhelmed by physics sometimes when doing labs, homework, or quizzes because the material is difficult for me to understand. I never liked science, and although physics is no easier than any of the other sciences i've taken so far, it is the most fun. I like the way i can relate physics to almost anything, and the demonstrations in class and the labs we do reflect the conepts. Physics is fun, but i often feel like there is no way i can conquer it.

My goal for the rest of the year is to gain a better understanding of the concepts i learn. I could also try to procrastinate less and manage my time better. I think i could put more effort into studying for physics and preparing for quizzes and tests. It's pretty tough with all the things for college and other classes, but if i put a little extra time into physics, i think i can improve at it.

skateboard

This weekend i decided to skateboard to my friend elysse's house to save gas. I stood on my board at the top of the hill, and thought of Newton's First Law, every object continues in its state of motion, until acted upon by a net force. I stood on my board at the top of the hill. I would have stayed in one place if it wasn't for the force of gravity increasing my velocity down the incline. The friction of my wheels rolling on the pavement as well as the air resistance from the wind blowing against me were both forces acting against the gravity; however, the force of gravity was stronger and therefore i kept on rolling. I soon realized that my velocity was becoming too great and i had to slow myself down. Luckily i always carry my umbrella in case of rain. I knew from physics that if i opened the umbrella, my surface area would increase, and therefore increase air resistance, so i opened it and held it behind me. I could feel it pull me back, but it still wasnt enough to counteract the forward force pulling me down the hill.

parachuting

Yesterday I visited the dentist and he was nice enough to let be choose a toy from the treasure chest. As searched through the box I saw sticky hands and bouncy balls and my first thought was, "wow, this box is filled with physics!" I chose the parachuting army man. When i got home I was throwing it up in the air. When it first begins to drop, the parachute is not fully opened and the army man falls quickly. When the parachute finally opens up, the man begins to fall much slower. I wonder what made this difference and realized it was air resistance. When i release the army man in the air there are two forces acting upon it, gravity and air resistance. A free-falling object on Earth has an acceleration of -9.8 m/s^2 due to gravity. However, this number ignores air resistance. When the man is in the air without the parachute opened, air resistance is only acting upon his body. The parachute increases surface area and causes an extra upward force, so that the army man will begin to accelerate in the upward direction or decelerate. This allows for the army man to make a safe landing unscathed.

ping pong

Today I was playing ping pong at my friend's house and realized that many aspects of physics were in the game. When I serve the ping pong ball, my paddle makes contact with the ball causing the ball's acceleration to increase. Velocity also increases as the ball, whose initial velocity was zero, flies over the net. As the ball reaches my friend, the rate at which the ball is accelerating decreases, and velocity decreases.

When my friend returns the ball, his paddle exerts a force upon the ball causing it to change direction and come back towards me. Because the direction and speed of the ball changes, velocity changes as well and becomes negative.

Playing ping pong also shows displacement which is the direction and distance of the shortest path between an initial and final position. Before I serve the ball, displacement is zero because it has not traveled any distance. The ping pong table is nine feet in length. As I serve the ball over the net, displacement changes. Once the ball reaches my opponent, displacement becomes +9.0 feet. As the ball returns back to me, displacement becomes negative. When the ping pong ball reaches its original starting position, displacement returns back to zero.