The figure shows a football in three common inflight configurations. 

Case (a) is a perfectly thrown spiral pass with a spin rate of 120 rev/min. 

Case (b) is a wobbly spiral pass again with a spin rate of 120 rev/min about its own axis, but with the axis wobbling through a total angle of 20°. 

Case (c) is an end-over-end place kick with a rotational rate of 120 rev/min. 

For each case, specify the values of p, θ, β, and ψ˙ as defined in this article. The moment of inertia about the long axis of the ball is 0.3 of that about the transverse axis of symmetry.

Transcribed Image Text:

20° (a) (b) (c)