Download Drag and Velocity

Coefficient of Drag
The force of drag can be calculated using FD = ½ C v2 A d.
1) You investigated two of these variables with coffee filters.
a) Which two were varied? How did you measure them?
Name _______________
b) What did you graph to get a straight line? Rearrange the equation to find a formula for the slope.
2) You investigated two of these variables with balloons.
a) Which two were varied? How did you measure them?
b) What did you graph to get a straight line? Rearrange the equation to find a formula for the slope.
3) What is d?
4) C is a constant called the coefficient of drag. It depends on the shape and surface material of the object. It
cannot be measured directly. Everything else is measured and C is calculated from those numbers.
a) Give an example of something with a high coefficient of drag.
b) Give an example of something with a low coefficient of drag.
c) Rearrange FD = ½ C v2 A d for C.
d) What are the units of C? Remember that force is measured in N which is the same as kg*m/s2.
5) Why must the object be falling at terminal velocity for these experimenst to work?
a) One reason involving forces
b) One reason involving velocities.
6) Calculating the coefficient of drag.
a) Describe how you measured the drag force.
b) Describe how you measured t the cross-sectional area his.
c) Describe how you measured the speed.
d) Calculate the coefficient of drag for your first object which was a ________________.
e) Calculate the coefficient of drag for your second object which was a ________________.
7) Comparing the coefficient of drag for different objects.
a) Fill in the table below with the class’s results.
Large Balloons
Small Balloons
Coffee Filters
Muffin Cups
b) What objects should have similar values? Explain.
Paper Plates
Styro. Plates