We are looking for the angular acceleration after the collision. Task a asks for the inertia. This was no problem. Task c asks for the remaining kinetic energy after the collision :-)
1. A door gets hit by a lump of clay with mass m=0.50 kg. The lump of clay has a velocity of v=10 m/s and hits the outer edge of the door at a right angle lodging itself in the door (See picture)
In task a) we used the formula (I=1/3*M*r^2) and calculated the inertia being 7 kgm^2/s.
In task b)...