Unit 3 Blogpost

Throughout this unit, most things we studied revolved around Newton's Third Law which states that, "Every action has an equal and opposite reaction." At first, this was hard to comprehend because in a car crash, one car is impacted more than the other, but how is that possible if they have equal and opposite reactions to each other? After learning more about what factors in to these problems, I learned that the acceleration of the respective cars has a huge impact on the result of the crash. If a truck and a sports car collided, the truck would have a bigger force not because it was going "faster" but because its acceleration was higher because of its greater mass.

A tug of war game is surprisingly similar to the car crash in that the weight of each team is irrelevant because the forces are equal and opposite. However, the amount of friction that the teams put in the floor determines the winner.
An easy example to help understand how forces work in perpendicular directions is which way a boat will go in a river. If the current is going downstream, and the boat is traveling to the right, the boat will go southeast in order to get to shore. A connection I made was using the special right triangles from Geometry last year in order to find the third velocity value. If two were labeled 3 and 4, I could assume that the hypotenuse would be 5, and that was comforting to have that knowledge up my sleeve.
My favorite topic we studied during Unit 3 was what forces happen in order for ocean tides on earth to do what they do. There are two types of tides that occur on earth, called Spring and Neap tides. The difference between the two is the amount of force the moon is pulling on earth with, and therefore how far the moon is from the earth. I know this because F~m and F~1/d. These formulas mean that Force and mass are directly proportional while Force and distance are inversely proportional. Spring tides occur when the sun, moon, and earth are perfectly lined up, while neap tides occur when the sun and earth are lined up, but the moon is off to the right or left of the earth. The results of these two tides are very different. Because F~1/d, the closer the moon is to earth, the greater force there will be. Spring tides create extreme high and low tides and neap tides are less extreme and normal. This is because when Spring tides occur, there are two strong forces on the earth: the sun and the moon. Although the sun does have a larger force on the earth because of its mass, some of that is diluted because of its far proximity to earth. That is why the moon has a greater affect on earth's tides. Tidal bulges occur when the moon is pulling on that part of the earth thus creating high tides. High tides occur simultaneously on opposite sides of the earth because the tide changes every six hours (from low to high). It takes twelve hours for a beach to have a high tide and then another one.

One of the biggest topics we learned about was momentum. Momentum is the measure of inertia in motion, and the symbol for momentum is p. The formula to find the momentum of an object is p=mv. If the momentum changes, then the mass and velocity increase as well. One phrase that was stressed throughout the section was that the momentum before a collision is ALWAYS equal to the momentum after the collision (p total before=p total after). After understanding momentum, we were ready to introduce Impulse (J) which is Force(time interval)=J. Another way to say this is that in relation to momentum, J=△p.
To find the velocity of two objects that recently collided, we would use the formula maVa+mbVb=ma+mb(Vab). By using the masses and velocities of two objects that become one, we can find the velocity of the new object.
After learning about this, we delved into the Law of Conservation of Momentum which states that the p total before = p total after. This law is vital for our understanding of momentum and how we solve for it.