Thanks guys, all points taken.
Magnet retained arm(finally some use out of those headphone magnets) or simply the use of marker for recording the motion of the pendulum is great.
And suspension by means of fishing line, I was thinking something with less stretch, perhaps some dacron or a few strips of really thin sheet metal to keep pendulum from rotating.
Two questions come up...
So far I've seen a few different versions of pendulum suspension - 1. by a single rod...usually in a cylindrical pendulum; 2. by four strings connected at four corners of the box shaped pendulum.
The first one is pretty much straight forward as to the point of the pendulum to take the reading from(assuming it's along the axis of the suspension cable/string/rod), but with a pendulum attached in four points the motion is somewhat linear? or am I mistaken?
Any way the above mentioned can be figured out during assembly...what bothers me the most is this...
Material of the pendulum, will a foam insert be a good idea? or will it dampen the impact throwing off the transfer of kinetic energy and as the result give an incorrect reading? Reason I'm asking...well shooting a block of wood might break some arrows...especially long ones....any ideas?
PS: Jake-owa...I've heard of a slightly different method, but still very similar to yours...two frame stretched papers with microphones connected to them were used to record and plot the time of impact on each.