Kelp on the Beach

Project Description

This project involved swinging a mass on a string in a circular motion and analyzing the motion (including forces, velocities, etc.) at four or more different radii. 

First, we selected our object, the sponge named Sponge Rob, and tied a string to it that was marked with tape every half meter. One person swung the sponge in a circle around their head at increasing radii (0.5m, 1m, 1.5m, and 2m), whilst another recorded using slow motion video. Using the mass of the object, the radius of the circle (as observed by the tape markings), and the period found at each point using the video data, we calculated the tangential velocity, centripetal acceleration, centripetal force, force of gravity, and force of tension on the string. 

To further investigate, we assumed the string had a breaking tension of 100lbs (445N), and attempted to calculate the tangential velocity and radius needed to swing Sponge Rob to break the string. Using air resistance and weight, we found the terminal velocity of our object and used the centripetal force formula to calculate the corresponding radius. 

Graphs

As radius increases, centripetal acceleration and force should decrease. However, the data collected at a 2m radius is an outlier found using a different video than the others, leading to an inconsistent trend in the data..

Content

Velocity: the displacement of an object with respect to time; the direction of velocity is tangent to the circle in rotational motion

Period: time per rotation (T = 1/f)

Acceleration (centripetal): (ac = v^2/r) change in velocity over time; centripetal acceleration is always towards the center of the circle 

Centripetal Force: (Fc = mv^2/r) force towards the center of the circle

Centrifugal Force: not a real force; the feeling of force outwards in a circular motion; the inertia of wanting to keep going in a straight line 

Apparent Weight: how heavy an object appears to be; the normal force acting on the object

Friction: force opposing motion

Air Resistance (Drag): friction force an object encounters when moving through air

Terminal Velocity: the maximum velocity of an object moving through fluid (air); occurs when the force of air resistance is equal to the force of weight opposing drag

Force of Tension: force exerted on a string, rope, wire, etc.

Newton's Law of Universal Gravitation: (Fg = Gm1m2/r^2) every object attracts every other object in the universe with a force proportional to the masses and inversely proportional to the distance squared 

Reflection

All things considered, this was a project I enjoyed the most this semester. My teammates and I cooperated well with one another, and we created an end product that was both fun and informative. 

Two areas where I demonstrated proficiency this semester included critical thinking and collaboration. I was able to work productively with my teams and made positive contributions to the success of each project. In terms of critical thinking, I was able to help solve problems when they came up in our projects and assignments. Especially when solving practice problems, I was able to find multiple ways to work out the solution to a question when one method was not effective.

However, communication and conscientious learning were areas that I could improve on. Although our presentations ran relatively smoothly, I could have written better speaker notes for myself and practiced to be more comfortable when giving the presentation. As a conscientious learner, I can manage my time better both in and outside of class so as not to cause myself more stress to finish work on time. I can also work on focusing and making good use of class time to complete assignments.