Friday, November 22, 2013

Physics News
Summer 2012 Olympics



 (1:09 – 1:19)

At the most recent Olympics, the London Summer 2012 Olympics, China took home the gold in the men’s synchronized 3 meter diving.  The pair that took home the gold was Luo Yontong and Qin Kai. Examining just one of the divers out of this pair, what would be his torque about the front support of the diving board if he were standing at the end? What is one diver’s angular speed in the straight position?

·      Calculate Torque

Qin’s Mass: 64 kg
Assumptions: 3-meter diving board has post (B) and another support post (A) 1.0 m out.

τ = Fr = (64kg)(9.8m/s2)(3.0m) = 1,881.6 mN = 1.9 x 103 mN



·      Angular speed in straight position?
Assumptions:
Moment of Inertia is reduced about 3.5 times when changing from straight position to tuck position
Rotations completed: 4.5
Rotations in tuck position: 4
Time to complete rotations: 2.0 seconds

I1w1 = I2w2
W2 = w1(I1/I2)
 = 4 rev       x   1    = 0.571 rad/s = .6 rad/s
     2.0 sec       3.5


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