iPad Battery

IPad Battery

The battery used in an iPad is a lithium-ion battery. Lithium is the element of choice in this case because it is highly reactive, meaning a lot of energy can be stored in its atomic bonds. All of this energy is what allows us to play games, search the web, read books, and utilize all of the features we have on our iPads without the battery losing its charge too fast. The word ion is very important to recognize when talking about these batteries because it has both positive and negative charges stored inside of the cell, and they are unbalanced. When remembering the "mountain" image, it's easier to understand why in the battery, the lithium ions move from the negative electrodes to the positive electrodes (because electrons move "up the hill" towards the positive ions, and this creates energy(before this process happens it is just potential energy among the cells).

(A picture of the path of the protons/electrons)

As shown in the picture below, when the ipad battery in plugged into the charger, the ions are moving from the positive side(cathode) to the negative side(anode). This is happening because carbon has a negative charge, lithium has a positive charge, and opposites attract. When the battery is removed from the charger, the lithium moves back to the positive side of the battery. All of this happens at a higher voltage than most other batteries, allowing us to have such a long battery life when using our iPads because the more voltage, the more potential energy, and the more potential energy, the more active energy being put to use in our iPads.

This is a helpful video to understand how the battery works. Although in this case it shows the battery being put to use in a car, it is the same idea with and iPad.

http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery.htm

http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm

Projectile Motion

Projectile Motion

       In this week's lab we analyzed projectile motion. We did did this by throwing a basketball into the air, and as soon as it left our hands it became a projectile. Because the main idea in this lab was forces in two dimensions, we analyzed both the x(horizontal) and y(vertical) dimensions of the ball. After doing this we concluded that in the x direction the only force acting upon the ball is gravity(a downward force), and that the the ball is moving at a constant speed horizontally in the x direction but not in a constant direction. When we analyzed the ball in the y direction we were able to see that it was accelerating but constantly slowing down.

Here is a visual of the force acting upon a projectile-GRAVITY

(disregard the interaction between the person and the earth)

X-Dimension

This velocity-time graph shows the velocity of the basketball in the x direction. After analyzing the graph with a best fit line, we can see that the slope is zero, meaning that the x-velocity is constant.

In this position-time graph we can see that the position of the basketball in the horizontal direction is changing at a constant rate from its initial position.

Y-Dimension

In this velocity-time graph we can see that the velocity of the ball in the y-direction(vertically) is always accelerating at -10m/s^2 (we get this from the slope) from the initial velocity.

In this position-time graph we can see that the position of the basketball in the y direction(vertical) is in the shape of a parabola because that is literally the path the ball takes in the vertical direction.