Projectile Motion

For this week's lab, we went down to the gym and played some basketball while measuring the projectile motion of the basketball. We used the Video Physics app to create motion maps from the video of the shot at the basket. Then, we created graphs for the x and y components, the position over time and a velocity over time graph in the horizontal direction (x) and the vertical direction (y). 

The graph to the left on top shows the x position over time.  The change in position over the change in time represents the slope, which is is constant.  The change in position over the change in time is also velocity, which is constant. The graph below to the left shows the x velocity over time.  The change in velocity over the change in time is acceleration.  Because the slope of the line in this graph is 0,  there is no acceleration and no net force.

The top graph to the right shows the y position over time. The change in position over the change in time is the slope and velocity. The slope is not constant--therefore, the object is accelerating. The bottom graph to the right shows the y velocity over time. The decreasing line crosses the x-axis, and at that moment the object has a velocity of 0, which means it is at its peak. The rest of the time it is decreasing.

Forces in 2D and Circular Function

In our first lab of the second semester, we used the kick discs to test the nature of normal, gravitational, and tension forces. We measured the x and y values and used SOH CAH TOA to find the magnitude. These x-components and y-components are independent from one another. By adding up the x-components and the y-components, we can calculate the net force to analyze these forces in 2D. By spinning the disc, we created a centripetal force.  For an object to move in a circle, you need to apply one force toward the center--this motion causes acceleration. To orbit means to travel in a circular path. Satellites and even other planets orbit the earth through the centripetal force of gravity.