While bowling one day, you begin to wonder about the inertia of a bowling pin. You know that balls and pins generally make elastic collisions and that your \(6.5-\mathrm{kg}\) bowling ball continues to move forward after a collision, even when you hit several pins to make a strike. As it happens, you have just managed to knock down nine of the ten pins, leaving only one pin upright at the end of the lane. You ask your friend to make a video of your next shot so that you can later carefully observe the initial and final velocities of your ball. Sure enough, you hit the remaining pin head-on (make the spare), and after a little video analysis you decide that your ball lost about \(40 \%\) of its initial speed when it hit the pin. What is the inertia of that pin?