First I will say that I based the difficulty rating for this cache not on how hard it is to it but how hard it may be to figure out how to get the log container into your hands. It's physically easy to get to it if you figure out how. You will get credit for the cache by simply logging in here after you find the cache. Only those that figure out the trick to obtaining the orange waterproof match container in which is the log get to sign it however. Now for the info that goes with this cache.
In 1686 Sir Isaac Newton presented his famous three laws of motion, the 3rd of which has to do with how part of this cache “works.” That however is for me to know and for you to figure out. 
The cache is interactive. Its contents are easy to find but it’ll be up to you to get your hands on the log! Please be sure to put things back together in the most compact way when you leave.
Newton's third law states, “For every action there is an equal and opposite reaction.” Hint, hint. This principle explains a lot about things where misconceptions abound. Because of this, every year I challenge my physical science students with these three questions. (1) How can a rocket lift off a pad that it does not push against? (2) How can a gun experience the same force as the bullet that is fired out the barrel? And (3) how does a wall push back when we push against it? 
The answers to these questions follow. (1) The rapidly expanding gas rushing out of the back end of the rocket requires a mighty push to get it going that fast. The push (the action) that is applied to the gas is also applied to the rocket but in the opposite direction (the reaction). If the rocket needed to push against the pad to move away from it, then the rocket could not continue to accelerate once the pad and even the air were left behind. The firing of a rocket is analogous to the firing of a gun. The gun “reacts” to the “action” that the expanding gases have on both it and the bullet being shoved out of the barrel. Likewise, the rocket recoils as each tiny particle of gas rockets out its nozzle. The rocket is more or less “kicked” along. The greater the mass of the gases leaving in a certain amount of time and the faster they shoot out of the rocket, the greater the kick the rocket experiences, hence, the faster it accelerates! (2) A given force on a bullet produces a much greater acceleration in the bullet than the same force does when applied to the gun. The reason for this is because the gun has a lot more mass. More massive things react more slowly to a given force, thank the Lord! Finally, (3) the force you apply to a wall is matched by the repulsions of untold numbers of atom orbiting electrons that you are trying to squeeze together. The harder you push, the closer they get, and a consequence, the more they repel each other, and you!
So, find the cache then find the logbook. Beware of the tree the cache is attached to. I set it up in the dark during a snow storm. Everybody was supposed to stay home but I was bound and determined to make full use of the snow-day that we received today. The falling snow made it beautiful and peaceful in the woods. The original contents of the container are a camouflaged hunting hat (slightly smaller then an adult size and stuffed up into the cache), Spy Kids 3D glasses, two small Superballs (bouncy balls), a couple toys, and a jeep travel bug.
By the way, when I set out to find this wooded location for this cache I somehow planted my left shoe on a big log, a dog log that is! I first noticed it all over my bike pedal. It was nasty!!!! What are the odds? Out in the woods, minding my own business and ‘splot’. I had to drive home with it that way too.