Action Figures Love Extreme Sports

Hey, we all love our 29.5 cm tall plastic action figures, and this unit is a fantastic experience for them.   Your doll of choice may be male or female, as long as it is appropriately clothed and its superpowers are not used for the duration of the unit.

Throughout this unit, you will have the use of the following digital equipment.   While you do not need to use all the probes for each experiment, you will need to collect data for analysis of net force in each case.   You should plan on completing at least three of the tasks in the time allotted (everyone must complete the demolition derby lab.


Available tools:

• dual-range force probe
• videocapture software
• accelerometer
• force plate
• stopwatch
• motion detector

Your mission, for each of these activities, will be to complete at least two trials, and analyze the data using Logger Pro data sets.  Equipment listed is suggested, but if you can figure out another way to do this using different probeware, go ahead.  A free-body diagram and other questions for reflection will also be required.

Good luck.  You control the destiny of your super action figure!

The BIG Questions

Which sport(s) have the biggest effect on your action figure in terms of g-forces?

How does safety gear impact the system design of extreme sports?

What is the impact in terms of net force upon your action figure?

Evaluation Rubric.

Cliff Diving!

Your 29.5 cm action figure will be cliff diving from an adventure point three to five times its height into a bucket of water.
What data can you capture to record the auspicious moment and calculate the net force at the beginning of the dive, before the action figure hits water, and as it slows down?

Document your process and efforts

Parachuting is Cool!

Links to consider

Parachute Basics
Air Resistance (NASA)
Parachute History (you may want to check out Historical Review)


EACH GROUP WILL NEED TO TURN IN A SET OF CALCULATIONS BASED ON THE INFORMATION BELOW.

Class Prep:  Measure the distance from the landing rail to the ground below

_____m

If we drop an object from the landing rail to the ground (assume no friction), we know the following:

v(i)=____m/s
a=____ m/s/s
d=____ m

What will be the time it takes for the object to land?


You will need to complete the Action Figure parachute jump three times.


1.  Measure the time it takes to drop the Barbie to the ground three times, using a stopwatch. Calculate the average time ______s

2. Using a force probe that is connected to a Logger pro, measure the Force weight of the Action Figure and chute.

3. Using a(g) = 9.8 m/s/s, determine the mass of Barbie/chute's   ____ kg.

4.  Now you have a slightly different system than the one we first considered.  We know the distance to the ground d=___ m, the initial velocity v(i)=____m/s, and the time(avg) of the three trials _____s

5.  Using the data in 4., calculate the net acceleration of your parachute.

6.  Draw a force diagram of the doll, the net force, the force weight, and the force up.

7.  Determine F(up).

**you may wish to have the Action Figure land on a force plate**



Take a picture of the doll, in its harness, AND a picture of the parachute and harness system.  Email it to me, along with a picture or shared document of your calculations.


Reflection (to be done on Monday)

Demolition Derby Testing!

The thrill  of the crash motivates demo derby enthusiasts.  Our action figure is no exception, which is why s/he needs a great safety harness and bumper arrangement.


Please do the following (Note:  as much as I would like to have an actual demo derby, you can simulate the experience by using a ramp, a pop can, and a wall.  Here is a sample diagram, although yours might be different.

:

• Create a three point harness that simulates a real seat-belt.   A chair with appropriate padding to prevent whiplash should also be included.
• Test the FRONT BUMPER with an accelerometer attached to your doll's lap.  Save the graphs and the data table.
• Repeat, but this time, use the BACK BUMPER.   Your doll will be facing uphill in this trial.   Again, save the graphs and the data table.
• Simulate a ROLLOVER COLLISION off of the ramp, where the accelerometer is in the seat belt. (Let the car go down the hill crookedly, so it rolls off.  Again, save the graphs and the data table.
• Document your car visually, including the entrance point and the seat belt.

Project Report

1.  Make a CLAIM of which BUMPER worked better.  Use screen shots of the data on the Logger Pro to provide EVIDENCE for the trial that worked best, and the trial that worked less effectively.

2.  Compare your ROLLOVER data to the BUMPER data.  Explain how effective you think this was as a structure and WHY. 

3.  Draw a force diagram for the car on the hill  and label the Fweight and the Fnormal

4.  Draw a force diagram for the car on the floor.  Label F(friction), Force(weight), Force(normal), F(applied) and F(net).  CAN YOU CALCULATE THE NUMERICAL VALUES OF ANY OF THESE THINGS?  If so, how can you do it?  Show example calculations (not just writing down values)

5.  Calculate how many g-forces the doll had acting on her by dividing the accelerometer value by 9.8 m/s/s, the value of 1 g.  

6.  How badly would Barbie have been hurt, do you think, based on the g-force information below from Wikipedia?

1) Vertical axis g-force:
a) positive: untrained: 5 g; trained, with special suit: 9 g
b) negative (drive blood to the head): - 3 g
c) instantaneous: 40 g
d) deadly: 100 g (record: 179 g)

2) Horizontal axis g-force
"The human body is considerably more able to survive g-forces that are perpendicular to the spine."
Untrained humans:
a) pushing the body backwards: 17 g
b) pushing the body forwards: 12 g


3) "Strongest g-forces survived by humans
Voluntarily: Colonel John Stapp in 1954 sustained 46.2 g in a rocket sled, while conducting research on the effects of human deceleration.
Involuntarily: Formula One racing car driver David Purley survived an estimated 179.8 g in 1977 when he decelerated from 173 km·h−1 (108 mph) to 0 in a distance of 66 cm (26 inches) after his throttle got stuck wide open and he hit a wall."
Source for all quotes and further information:
http://en.wikipedia.org/wiki/G-force 

Reflection:

• Explain your design process and seat belt rationale.
• How well did your bumper work in terms of a crumple zone?
• Does Barbie survive your collisions?
• Was the Barbie protected from whiplash in your vehicle? How do you know?
• What was the effectiveness  of the roll-cage?  
• What else have you learned?

Bungee Jumping!

Barbie is highlighted here, but in reality all sorts of people have bungee jumped

There are many types of harnesses and jumps for Barbie.   You will detail the type of harness(es) used and the type of jumps you give for each Barbie.  You must try two different jump styles for each material and keep a careful table of data.

Details on harnesses and jump styles can be found at:   http://www.bungeeamerica.com/jump-styles.html



Set up the equipment, attaching a Barbie on a cord to the force probe.  Connect an accelerometer to Barbie and her harness. Remember that you need to tell the Logger Pro what type of force probe is attached...it may not do so automatically.

Place a motion sensor below Barbie on the ground. Determine Barbie's Fw, and F(net) and Fup Your calculations must be shown at the moment that Barbie is at the maximum extension of the rope going DOWNWARD. All calculations must be summarized in a table when you turn in the lab.  S

Procedures:
Produce as least 6 different graphs by dropping Barbie with different cords. Use the evidence to collect a rationale for the common use of rubber as a bungee cord, and whether it is supported by your data.


Print or save your graphs for each "jump". Clearly indicate which cord or material was used. Also include information such as the amount of force and the time over which the force was applied. Record any relevant observations you saw during the jump.  Hint (this works best if you upload each of the five files to a Google Doc folder, and then share down to your individual machine)

Calculate the Fnet on a 29,5 cm or similar doll and theg-force for each jump using sketch of the graph and data from your trials.  This must be accompanied by at least ONE free body diagram.


Group:  Send me the files you created, with your name, the jump type, and the harness type labeled.

Individual WRITEUP

• Is it possible to design a multi-purpose harness for all sports so that net force is distributed across the Action Figure? Explain. This should be based on data you gathered when Barbie parachuted, your seatbelt harness, and this lab.  A picture may be helpful here.

• Explain how the total time for the Action Figure to stop jumping can affect a force distribution. (Think carefully: F=ma, but a = change in velocity/change in time)--the motion detector will be helpful her.

• Based on your data, is it possible to argue that there is a better material for a bungie jump than rubber? Why or why not?
• 
  
• Your seatbelt lab, your parachute jump, and the bungie jump all allowed you to gather g-force acceleration data.  Create a table of g-force information and tell me which is the safest situation:  the Action Figure bumper crash,  the bungee jumping, or something else?   

• What do these labs tell you about extreme sports?

• Write a 4-10 sentence summary of what you have learned.

New Frontiers!

What other adventures could you document with your 29.5 cm action figure  that parallel extreme sports?  This problem is worth an additional 15 points for a well thought rationale and execution of a new idea.  Documentation must include a Claim, Evidence (numerical and visual), Reasoning, and a net force diagram for a model.