Introducing Electricity

An electric charge causes a force between objects. Unlike momentum or acceleration, people cannot see electrically charged atoms with their own eyes, let alone the particles that compose them. The charge of an object is either positive or negative. This picture contains a fork and a cup. The fork is made out of metal, which is a conductor. Conductors are materials that transfer electrons easily because they want to give them up. This is characteristic of a positive charge. Meanwhile, the cup is created with glass, which is an insulator. Insulators do not transfer electrons easily because they want to take electrons, which is a quality of a negative charge.

First Semester Review

Overall, I found this semester of physics to be both difficult and enlightening. The equations used in physics definitely enforce mathematics, mostly algebra but also trigonometry when three-dimensional motion is involved. Since most of the physics units involved vector quantities, negative and positive values determine if the direction of an object remains the same. At times, I was not sure about how to work with certain ideas. Since I did not always understand the concepts of the unit, my ability to use them was often hindered. My most consistent problem during this semester involved confusing one definition with another. For instance, I would mistake acceleration with momentum, which made me incorrectly believe that momentum and acceleration would be conserved during a collision. In reality, when two unequally massive objects collide, they must have different accelerations in order to have the same force of impact.
Since Christmas is approaching, these pictures display a festively dressed dog perched near a staircase. One of the main principles of this course seems to be that even a mundane setting can highlight physics in some way. If the dog was pushed down the staircase's handrail, the dog will fall downwards because gravity forces objects in that direction. Since the rail lacks friction, it doesn't prevent the dog from moving. Also, as the dog travels, its potential energy turns into kinetic energy. In essence, physics is both basic and puzzling to those who are learning about it. Although physics can still perplex me, I do appreciate its relevance to the world. 

A Work Out

In physics, work is defined as a scalar quantity of an object's change in energy. Energy is directly related to force and displacement. As a result, it is measured in joules, which is the product of Newtons and meters. Like matter and momentum, energy is neither created nor destroyed in an isolated system. However, the energy can transform into other forms. In these blurry pictures, I bounced an exercise ball on the ground. The energy that I lost from bouncing the ball is equal to the energy gained by the ball. As the ball bounces, some of its initial energy turns into heat and sound, so the height of its bounce decreases as time continues.

Egg Drop

As a way to observe momentum, my classmates were divided into groups that had to drop eggs without breaking them as they landed on either the road or the sidewalk. In order to prevent the egg from being harmed, my group used three car sponges, a rubber band, and rope to enclose it. A hole was cut in the middle sponge as a place for the egg. On Wednesday, one of my group members dropped it from the designated area and I retrieved it from the road. A few moments later, I discovered that my group's egg survived its fall. Basically, the egg did not crack because its enclosure increased its contact time with the road. As a result, the average force on the egg decreased because the sponges absorbed some of the egg's force.

More Momentum Moments

 

Impulse often demonstrates the impact of a force on an object during a certain period of time based on the product of the object's mass and velocity, which is the definition of momentum. The average force on the object changes due to contact time. When an object falls straight to the ground, the contact time between them is small so the object feels a large amount of impact by the force. In order to reduce the amount of impact between the objects, the contact time between them must increase. In these two photographs, a bear falls on the floor and then on a pillow. Due to the pillow, the average force of the ground has less of an impact on the bear because the force distributes itself over a longer period of time.

Conservation

According to a concept called conservation of momentum, momentum is like matter in the sense that it cannot be formed or destroyed out of nowhere. During a collision in a closed system, the momentum of each object in the system is equal and opposite of each other. If the momentum of one object is 4 kg*m/s, the momentum of the other object would be -4 kg*m/s. As seen in these photographs, a pair of remote controls collided into each other. When the objects push on each other, their final positions are practically mirrors of one another. In this instance, objects with the same mass and the same change in velocity will have the same magnitude of momentum.

Comparing Momentum

 

 

By definition, linear momentum is a vector that is the product of the object's mass and its velocity. The object also moves in a straight line in order for the momentum to be linear. The SI unit for the quantity is kg * m/s. In the photograph on the top right corner, the pen featured on the top left was thrown at the package of crackers. In the photograph on the bottom right corner, the tape measurer seen in the bottom left was thrown. I threw each item at the same velocity. However, the crackers traveled farther when the tape measurer was thrown at it. This is due to the fact that the tape measurer has more mass than the pen. Since the objects have different masses, the momenta of the objects are not the same even though both had the same speed.