Forces in 2D and Circular Motion (Hover Disc)
What does it mean to analyze forces in 2D?
To get a better picture of what a 2D force is, it's easier to know that the sketch of a 1D force is simply a line. So to get a 2D force you must add another line, and when you add this other "line" or another dimension, your force now had length and width. The length and width are represented on the graph by the x and y axes.
How do forces cause objects to move in a circle?
Forces Cause objects to move in a circle through centripetal force. To better understand this process, it helps to know the centripetal means "center-pointing." So while the object is being pulled toward the center through tension force, because it is going at a constant speed, but also accelerating, it remains in a circle. This may sound confusing, but we learned that acceleration doesn't just mean a change in speed, it can also mean a change in direction. So because our object is moving at a constant speed but also changing direction, it is accelerating.
What does it mean to be in orbit?
To be in orbit means when one object follows a "curved path," or moves in a circle around another object, while also being acted upon by centripetal force.
How do satellites orbit planets?
In order for a satellite to successfully orbit a planet, it must be going at the correct constant speed. The satellite is being pulled in toward the planet through gravity. When the satellite reaches its correct speed, centripetal force kicks in to keep the satellite from falling towards the planet, because as weird as it may seem, satellites are always falling. In the lab, when we kept the hover disc moving at a constant speed it's motion remained in a circle. If we were to slow it down, the disc would move in to the center towards us, and we were to speed the disc up we would eventually lose control and it would fly off.
How do planets orbit the sun?
Planets orbit the sun because the sun is the centripetal force acting upon them, very similar to how satellites orbit around the planets. So each of the planets are falling, and want go in a straight line, but it is the gravitational pull that is preventing them from doing that. So don't ever let anybody tell you there is no gravity in space! And again because their direction is not constant, the planets are accelerating around the sun. Because both the sun and the planets are curved, the planets are falling around the sun, but missing it's surface as it moves in a circle.
