Densities+And+Velocity

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Title
Densities And Terminal Velocities

Broad Question
Does the density of an object change the terminal velocity?

Specific Question
If I modify the density of a tennis ball, will its terminal velocity change?

Hypothesis
If the density of an the tennis ball is higher, the higher the terminal velocity of the object.

Variables That Need To Be Controlled:
Distance and angle ball flies.

Vocabulary List That Needs Explanation
Terminal Velocity: the max speed something will go before it drops.

General Plan
I will change the density of a tennis ball by adding some type of liquid or gas to change the density. Then, I will use a tennis ball launcher to shoot a tennis ball and find its speed. Then, i will turn speed into terminal velocity. I will record the data in a data table, average the numbers, and use the average to see which density of ball has a higher or lower terminal velocity.

Potential Problems And Solutions
I can't measure the speed of the tennis ball. A modified tennis ball won't shoot.

Safety Or Environmental Concerns
Someone getting hit with a ball.

Experimental Design
= Controlled, manipulated experiment =

What is your experimental unit?
Terminal Velocity.

Number Of Trials:
5

Number Of Subjects In Each trial:
2

Number of Observations:
5

When data will be collected
My data will be collected the 16th-24th of February.

Where will data be collected?:
Cranmore and my house

Resources and Budget Table

 * Item || Number needed || Where I will get this || Cost ||
 * Tennis ball shooter || 1 || Cranmore || not sure ||
 * Tennis balls || 10 || Walmart || not sure ||
 * Radar gun app || 1 || App store || 1.99 ||
 * Tennis balls || 10 || Walmart || not sure ||
 * Radar gun app || 1 || App store || 1.99 ||

Detailed Procedure
1. Test the shooting speed and angle 2. Take speed of tennis ball 3. Record in table 4. Change the speed to the terminal velocity 5. Repeat steps 2-4 four more times 6. Average the terminal velocities 7. Repeat with a modified ball 8. Compare

Data Table

 * || 0 BB's || 50 BB's || 100 BB's || 150 BB's ||
 * #1 || 153 || 203 || 227 || 271 ||
 * #2 || 171 || 221 || 231 || 263 ||
 * #3 || 155 || 196 || 251 || 250 ||
 * #4 || 139 || 221 || 237 || 249 ||
 * #5 || 187 || 189 || 243 || 269 ||
 * Averages || 161 || 206 || 237.8 || 260.4 ||
 * Averages || 161 || 206 || 237.8 || 260.4 ||

Results
The higher the density, the higher the the terminal velocity.

Conclusion
====My conclusion is that if two objects have the same shape but different densities, the one with a higher density would have a higher terminal velocity. This is true with most objects. The gravitational pull will pull harder on things with a higher mass.====

Benefit to Community and/or Science
This will further the understanding of speed and mass for younger people who don't quite grasp physics.

Background Research
The mass of a standard BB pellet is roughly five grams depending on factors like a difference in the making or rust that has developed on the BB. Terminal velocity is measured in. Mathematically, terminal velocity—without considering buoyancy effects—is given by  where = terminal velocity, = mass of the falling object,

[[image:http://upload.wikimedia.org/math/f/7/f/f7f177957cf064a93e9811df8fe65ed1.png caption="\rho"]] = Density of the fluid through which the object is falling, and
= projected area of the object.The weight of a standard Tennis ball is roughly 56 to 59.4 grams.