This weekend, I went the Punahou Carnival and saw a lot of physics. The ride called the ring of fire is a ride that takes you in a loop. It slowly speeds up until you only have enough speed to make a full revolution. This ride reminded me of centripetal force. The equation for Fc=mass times velocity squared over the radius of the circle. The roller coaster feels normal force from the tracks and that helps the centripetal force. At the highest point at the slowest speed the normal force of the track is zero.

In this picture there are two different sized wrenches. If you want to maximize the amount of torque you can produce, you would want to use the longer one. In the equation lever arm times the force equals torque, if you increase the lever arm you can increase the torque. That’s why it is easier to loosen a bolt with a long handle than a short handle. If you need more torque on a bolt, all you need to do is lengthen the lever arm.

extra credit

In the video, I used a charged balloon to make the water bend. This happens because as the balloon rubs against my head, it gains electrons from my hair. The rubber balloon is an insulator so all the electrons stay in one place and don’t spread around the balloon. The electrons cause a negative charge on the balloon. When the balloon comes close to the water, the positive charges in the water move closer the balloon because opposites attract. The negative charges move away from the balloon because like charges push each other away. This polarization of the water causes it to bend because the pull of the positive water and negative balloon is stronger than the repulsive forces of the negative charges.

static magic

In this picture, I wanted to see the effects of static electricity. I rubbed a balloon on my hair and put it on the wall and it magically stayed on the wall. I used friction to make static electricity. When I rubbed the balloon to my head, the friction that was created caused some of the electrons from my head jump to the balloon. Since the balloon isn’t a conductor the negatively charged electrons stayed in a concentrated area. The negatively charged area on the balloon touches the wall and all the positive charges on the wall want to come closer to the balloon and all the negative charges want to go away from the balloon. This causes something called polarization of the wall because now there are two different poles a positive and negative charge but the net charge is still zero.

In this picture, I was driving down the Pali Highway and noticed that the turns are slanted. I was driving down the Pali coming from town and I noticed the big turn at the bottom of the Pali. I was slanted toward the center. They slat the highway towards the center to increase the amount of force keeping you in a circle. If you make a turn on a flat road you are using only friction to keep you moving in a circle. When you slant the curve allows you to make turns at faster speeds because you and friction and cosine of the normal force keeping you in a circle.

hitting eachother

In this picture the red ball collided into the purple ball in a bouncy collision. In Physics we are learning about collisions and the conservation of momentum. When an object hits another object the momentum is conserved. This type of collision is called an inelastic collision. The collision in the picture shows a two-kilogram ball hitting a stationary one-kilogram ball. The red ball hit the purple ball and glanced off to the side. The purple ball moved straight back. This collision is a perfect example of a two dimensional collision.

potential energy

Since we are learning about energy I thought I should make my journal about energy. In the picture, my camera case is at rest on top of the garbage can. Even though the camera case is not moving it has different amounts of potential energy depending where you want to set the reference line. If you compare the high of the camera case to the ground, it has potential energy. If you want to compare the high of the case with the high of the trashcan then it has no potential energy. Potential energy is measured by the mass times the acceleration of gravity times the height of the object. If the case were to fall to the ground, the potential energy in the case would turn into kinetic energy. All the potential energy will turn into kinetic energy when the case hits the ground. Kinetic energy is calculated by half the mass times velocity squared. Many objects around the house have potential energy.