Lindsey Franklin

Ryan Connolly

Jason Carsick

Purpose: During our literary search, we identified many elements of skydiving to have equally unique effects on the time that it took the diver to reach terminal velocity. The surface area of the diver (thus his/her position), the height that he/she falls from, the design of the parachute, and the mass of thejumper all effect the terminal velocity of the jump. In fact, the equation for terminal velocity is the square root of (2mg/CdAp), where Cd is the coefficient of drag, A is the surface area, and p is the atmospheric pressure. For this experiment, however, we will only be using surface area and mass as our independent variables. Thus, the purpose of our experiment is to determine and understand the effects that surface area and mass have on a skydiver’s terminal velocity.

Controlled Variables: Because we will not be able to vary atmospheric pressure (which changes with the altitude, a.k.a. height) in our classroom, we will use the atmospheric pressure as our controlled variable. In other words, the height of the jumper will not change. Furthermore, the resistance on the "jumper" will not change as we will be using a cart on a track to stimulate the diver’s fall, and thus the resistance of the cart will not change.

Hypothesis: We believe that by increasing the surface area, the terminal velocity will decrease. We also believe that by increasing the mass, the force of gravity will be larger, and thus the diver will accelerate for a longer time, and it will take a longer period of time for the two forces (force or gravity and force of drag, which act opposite one another) to become even in a terminal velocity.

• One physics lab track (2 meters long), positioned at a steep slope, in order to simulate the force of gravity on the diver.
• One cart
• Three bars of different masses-each of which will have a minimal mass
• Three plastic "shapes" of different surface areas

1. Place the cart on the track without any bars (incorporate a constant piece of plastic to allow the cart to reach terminal velocity). Push the cart so it moves along the track, measure the velocity by using the photogate and motion sensor and then by viewing the velocity vs. time graph from the computer attached to the track.
2. Add one bar to the cart and repeat step one.
3. Add a second bar to the cart and repeat step one.
4. Add a third bar to the cart and repeat step one
5. Through the velocity vs. time graphs on your computer, record the terminal velocity and the time the cart reached terminal velocity.

Step 1 Step 2