A bullet is shot through two cardboard disks attached a distance D apart to a shaft turning with a rotational period T, as shown.http://session.masteringphysics.com/problemAsset/1011045/30/MRB_rr_8_a.jpg

Derive a formula for the bullet speed in terms of D , T , and a measured angle theta between the position of the hole in the first disk and that of the hole in the second

Question

A bullet is shot through two cardboard disks attached a distance D apart to a shaft turning with a rotational period T, as shown.http://session.masteringphysics.com/problemAsset/1011045/30/MRB_rr_8_a.jpg

Derive a formula for the bullet speed  in terms of D , T , and a measured angle theta between the position of the hole in the first disk and that of the hole in the second

anonymous · Answer

Start with the velocity of the bullet equal to the distance between the disks, D divided by the time it takes the bullet to travel between the disks, t.
$$v =\frac{ D }{t }$$  
You need to determine an expression for t involving T and θ.
T is the period or the amount of time it takes for the disc to make one complete revolution.