Unit 2 Blog Reflection

In unit two we started off learning about Newton’s second law of motion, which states that acceleration is directly proportional to force and inversely proportional to mass. This law can be read as a=f net / mass. With this law it was also necessary to learn that weight = (mass)(gravity). Weight is measured in newtons while mass is measured in kilograms. Next we learned about free fall excluding air resistance. An object in free fall, falls with an acceleration of 9.8 m/s^2. Knowing this, we learned how to calculate how long it is going to take for something to fall simply by knowing the height it falls from or vise versa. For example, when we calculated the height of 3^rd Anderson. After dropping a ball multiple times and taking the average time it took for the ball to reach the ground, we calculated the height. We took our average time and plugged it into the distance equation, d=1/2gt^2 and solved for d. This brought us to the approximate height of 3^rd Anderson. During free fall an object is constantly accelerating at a rate of 9.8m/s^2 until it reaches the ground.

Projectile motion is when something is pushed with a force and is projected through the air. For example, an airplane dropping a box. When an airplane drops a box the box is going to fall at 9.8 m/s^2 vertically, but the horizontal speed is going to remain constant through the reasoning of Newton’s first law. In order to find the vertical distance or time you are going to use the same distance equation that you would use for free fall, d=1/2gt^2. However for the horizontal velocity of an object you are going to use velocity=distance/time. For example, if you wanted to know how far in advance a plane should drop a box in order to reach a certain target you are going to use the formula v=d/t and solve for d.

After learning about projectile motion we learned about objects falling through the air. An object falling through air and an object in free fall are completely different. An object falling through the air is going to increase velocity and accelerate less and less until it reaches a point of constant velocity and zero acceleration. The object is going to reach a constant velocity when the net force of the object is zero. When an object falls, the force of gravity pulls it down according to its weight. The faster the velocity of the object the larger the force of air is going to be on the object. The object falling through the air is going to keep increasing its velocity until the force of air is large enough to subtract to zero when in accordance with the force of weight. An object with a greater weight is going to have to travel faster in order to reach a constant velocity because the force of air is going to need to be greater in order to reach a net force of zero.

Lastly, we learned about throwing things up at an angle. When something is thrown up at an angle you can calculate how much time it spends in the air by using the force of gravity acting on the force exerted on the object. When you find the time, you can calculate how far the object went. Throughout the flight of the object the horizontal velocity is going to stay the same and the vertical acceleration is going to remain at 9.8 m/s^2 at all times, even when the objects vertical velocity is at zero. At the peak of the objects path the velocity is going to be only the horizontal since the vertical velocity is going to be at zero. All calculations pertaining to the vertical velocity or time can be found using the formula d=1/2gt^2. All calculation pertaining to the object horizontal motion can be found with v=d/t.