A field goal kicker kicks a football off the turf and it clears the uprights (wh

Question

A field goal kicker kicks a football off the turf and it clears the uprights (which are 10 feet off the ground) by 6 feet. The kicker kicked the ball from the 30 yard line, and the field goal posts are at the back end of the endzone, which is 10 yards deep. An NFL football has a mass of 0.40 kg. The moment of inertia of an NFL football rotating in a perfect spiral (so rotating around the long axis) is 0.00194 kg m^2. The moment of inertia for a football rotating around an axis perpendicular to the long axis (so flipping end over end) is 0.00321 kg m^2. The kicker's foot bit the ball 1 cm to the side of the long axis (inducing spiraling motion) and 3 cm away from the center of the football along the long axis (inducing end-over-end motion). When the ball cleared the uprights, how fast was it spiraling and how fast was it flipping end over end, in revolutions per minute?

Explanation / Answer

More information required to answer the question. Why

1. Moment of intertia of a rigid body is a tensor that determines the torque needed for a deisred angular acceleration about a rotational axis.

2. Spiraling Speed / Flipping Speed is a function of time.

3. The object that is rotating at certain angular velocity will remain rotating unless it is acted upon by an external torque.

With above three in place, we need to know when the ball, lets say from rest gained some peak speed (what was that) and as it was crossing the uprights, it would decelerate, what was the speed at which it crossed.

This information would help us in determining spiraling and flipping rpms

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