Week 21 Reflection

This week in physics we truly started and explored our new unit, gravitational force. We began looking at the orbits of the planets, the forces they exert on one another, how distance can affect the force, and hypothetical questions if the orbits were to be altered. This unit is closely related to the centripetal force unit, as the orbits are just like a stopper on the end of the string, and the same rules apply in the solar system.

I learned that the closer the earth is to the sun, the greater the sun's gravitational pull on the earth. And because the earth orbits the sun on an elliptical path, the force acting on the earth changes. So as the earth is farther away from the sun, less gravitational force is pulling it in toward the center of the solar system. This relates to a pair if magnets. The closer the magnets are to each other, the greater the attraction between them, and the farther away, the less pull. In addition, the closer the earth is to the sun, the greater it's velocity. I always thought that we continued at a constant speed as we orbited the sun, but the velocity is actually changing depending on when the earth is in its orbit.

Hypothetical questions regarding the planets and their size/force changes proved to be a difficult topic for me to understand at first, but I now understand it after going over it with the class more. If you were to double the mass of the sun, it would double the sun's gravitational pull. However, if you double the distance between the sun and the earth, the gravitational pull would actually be a fourth of the initial amount. This is because the distance is squares in the equation, but the mass is not. This was confusing in the beginning, but I feel I have a good grasp of the concept now.

Something that really surprised me was that the moon in fact doesn't orbit the earth at all; it only orbits the sun. I couldn't believe I've gone my whole life thinking that the moon orbits both the earth and the sun. It's an illusion that the moon orbits the earth and it is actually a snake-like motion between the moon an the earth. You learn new things everyday :)

I attached the answer key that really helped me prepare for the assessment today!