- Modelling Skydiving with Parachute Opening_parameterized1491.jpg
- Modelling Skydiving with Parachute Opening_parameterized0000.jpg
- ModellingSkydivingwithParachuteOpening_forLookang.docx

Software Requirements

Credits

Author: Tan Kim Kia
Contact: This email address is being protected from spambots. You need JavaScript enabled to view it. | This email address is being protected from spambots. You need JavaScript enabled to view it.

end faq

Reference:

http://tankimkia.blogspot.sg/2015/10/modelling-skydiving-with-tracker.html?spref=fb

 https://drive.google.com/folderview?id=0Bw72rpuy2MMLRUFtM1c1VzM2Rk0&usp=sharing#

Modelling Skydiving with Tracker Software

Fy = if(t<35,m*g-A_h*0.5*d*Cd*vy^2,if(t<55,m*g-0.5*d*Cd2*A_p*vy^2,if(vy>0,-m*g,0)))

Model B(Blue): Parachute opens fully immediately T = 0

Fy = if(t<35,m*g-A_h*0.5*d*Cd*vy^2,if(t<35+T,m*g-0.5*d*Cd2*(A_h+(t-35)/T*A_p)*vy^2,if(t<55,m*g-0.5*d*Cd2*(A_h+A_p)*vy^2,if(vy>0,-m*g,0))))

Velocity-time graph for Model A:

Velocity-time graph for Model B:

Comparison of Velocity-time graph for Model A & B:

Acceleration-time graph - Model B compared to Model A    

 Conclusion

Model A’s deceleration is 3.1g, which is realistically small, and therefore, it is believeable the correct answer? 

Model B has a deceleration of 17g, which is unrealistic big and likely to cause hurt on the parachutist, which is the examiners answer of B.

I think it is a bad idea to open the parachute immediate while the parachutist is falling at 40 m/s. In real life, according to a Discovery Education Channel video (https://www.youtube.com/watch?v=ur40O6nQHsw), the parachute takes about 2-3 seconds to open fully, linking back to Singapore O Level Physics question: 5058/2010/P1 Q3, the answer is still C. What do you think? post your comments and discuss!

Ideas for teaching and demonstration:

Adjust the parameters and compare the velocity-time graph and acceleration-time graph. 

Download the Tracker zip file for Skydiving Modelling. 

You may find the free TRACKER Software at http://www.cabrillo.edu/~dbrown/tracker/

Related Singapore O Level Physics question: 5058/2010/P1 Q3

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