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Unreasonable ResultsA gymnast doing a forward flip lands
Chapter 10, Problem 19(choose chapter or problem)
Problem 19PE
Unreasonable Results
A gymnast doing a forward flip lands on the mat and exerts a 500-N · m torque to slow and then reverse her angular velocity. Her initial angular velocity is 10.0 rad/s, and her moment of inertia is 0.050 kg ⋅ m2. (a) What time is required for her to exactly reverse her spin? (b) What is unreasonable about the result? (c) Which premises are unreasonable or inconsistent?
Questions & Answers
QUESTION:
Problem 19PE
Unreasonable Results
A gymnast doing a forward flip lands on the mat and exerts a 500-N · m torque to slow and then reverse her angular velocity. Her initial angular velocity is 10.0 rad/s, and her moment of inertia is 0.050 kg ⋅ m2. (a) What time is required for her to exactly reverse her spin? (b) What is unreasonable about the result? (c) Which premises are unreasonable or inconsistent?
ANSWER:
Solution
Step 1 of 3
A gymnast is doing a forward flip. Given that she exerts a torque that is , initial angular velocity is and the moment of inertia is
Now we have to find the angular acceleration
where M.I is Moment of inertia
where = Force, and = radius.
Since torque and moment of inertia is given by substituting the above values we get
