Newton's Second Law is an equation that relates Acceleration, Force, and Mass. This equation is a=fnet/m, which means that Acceleration is proportional to Force, and Inversely proportional to Mass.
Falling Through The Air:
When falling through the air, the concept of Air Resistance must be accounted for. Air resistance is the force that air pushes against an object as the object is moving through it. Another key term for falling through the air Terminal Velocity.
Terminal Velocity is when the force of Air Resistance on an object is equal to the force of gravity on it, therefore the net force on the object is zero. Keep in mind that even though the net force and accelerations are zero, the object is still moving at a constant rate. Two things that increase the force of air resistance are surface area and speed. Supposing you have two objects with the same surface area and different masses, the one with a higher mass will have to reach a higher speed to have the force of air resistance on it equal its weight, therefore this terminal velocity will be higher than that of an object with less weight/mass.
Terminal Velocity is present when someone is skydiving. When first stepping out of a plane or aircraft, keep in mind that your velocity is 0 m/s as you aren't yet moving, and acceleration is 10m/s^2 because the force of gravity is always present on an object. After one second, your speed will be 10 m/s. After 3 seconds your velocity will be 20 m/s and so on. When solving for fnet, we can use fweight-fair.
After deploying a parachute, your surface area will be increased, and therefore your net force will become negative. This will give you a negative acceleration, otherwise known as accelerating upward. As we learned before, if an object's acceleration and velocity are in opposite directions the object is slowing down. Even though your acceleration is negative, you are still moving downward at a decreasing rate.
Free Fall
Free fall is achieved when gravity is the only force acting on an object and there is no air resistance. When in free fall, we can use the equation d=1/2gt^2 for vertical components of problems as well as v=dt because gravity is the only force acting on it. For the horizontal component of a problem we can use v=d/t, this horizontal velocity will remain constant.
Throwing a Ball Straight Up:
When throwing a ball straight up, it is important to remember that we start at the time t=0s. When solving these problems, we must note that we assume the object is in free fall, therefore the only force acting on the object is gravity. Take for example a ball that is thrown straight up with an initial speed of 20 m/s. As the object's acceleration is 10m/s^2 towards the ground, its speed will decrease by 10 m/s every second it is in the air. Knowing this, the object will reach the top of its path in 3 seconds, when its speed= zero. Then it begins its descent which takes the same time that it took to reach the top of its path. We can use the equation d=1/2gt^2 for these problems.
Falling at an Angle:
When falling at an angle, we again assume an object is in free fall. The horizontal component of velocity will remain the same throughout the projectile's flight. We can again use d=1/2gt^2 for vertical distance and v=gt for vertical velocity. Gravity will be the only force accelerating the projectile.We can use v=d/ for the vertical component of the projectile.
Throwing objects at an angle:
When throwing an object at an angle, we must consider the flight path of the projectile as a parabola. From its highest point (halfway through its flight) we can use d=1/2gt^2 for its height. We must also consider the angle of the throw, as we can use special triangles to help us solve for the actual velocity of the object instead of having to use the Pythagorean theorem a lot.
What I have Found Difficult about what I have studied is finding the height of a thrown object at a certain time during its flight.
I overcame these struggles by reviewing with friends and taking better notes about the subject..
My effort towards the class have been reasonable and I do everything to the best of my ability in the class. Homework is an area that I find i succeed at, as well as quizzes and tests.
I see myself persisting in my efforts in this class and continuing to try my hardest. I think I work well in group settings, trying to contribute ideas to the group as often as I can and trying to be helpful. My self confidence in this class helps my overall self confidence in school and helps motivate me to work hard in all my classes.
Part B:
A connection between what we studied and life that I see every day is the flight of a thrown football. I can relate each and every one of the concepts we learned to what i see on a football field every day.
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