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Grade 11Mechanics

A discus can be thrown farther against a 25-mi/h wind than with it. What is the explanation? (Hint: Think about dynamic lift and drag.)

Profile image of Radhika Batra
11 Years agoGrade 11
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1 Answer

Profile image of Kevin Nash
11 Years ago
When the discus is thrown against the wind, the air layer will flow into it. While moving in the air, it is rapidly rotating. Due to this, there is an air layer which circulates around it. So, the velocity above the discus will be higher than below it. According to Bernoulli’s equation, the pressure above the discus will be lower than below it. The air will exert a net force on the discus which have component perpendicular and parallel to the flow of air. The perpendicular component provides the dynamic lift force on the discus and the parallel component the drag force. Therefore, the discus moves farther than against the wind that with it.
If it is moving along with air, the dynamic lift force will act downward. This effect the distance travelled by the discuss.

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