In: Physics
An open door of mass 5m and width L is at rest when it is struck
by a thrown ball of clay of mass m. The ball is moving at a
constant velocity ? ⃗ = −??̂ and hits the door a distance L/2 from
the rotation axis through the hinges. The clay ball strikes
perpendicular to the door face and sticks after it hits. Neglect
the thickness of the hinges. All calculations must be carried with
good, consistent vector notation. Simplify all results and write in
terms of known quantities.
(a) Calculate the initial angular momentum vector of the door+clay
system and state any assumptions you make.
(b) Calculate the final rotational inertia of the door + clay
system.
(c) Starting from first principles, calculate the final angular
velocity vector of the door+clay system and explain whether this
result is reasonable.
(d) Calculate the percentage change in kinetic energy of the
door+clay system as a result of the collision, then use the result
to explain what percentage of the total mechanical energy was
dissipated in the collision.