Editing Hammer (section)

===Effect of the head's mass===
The amount of energy delivered to the target by the hammer-blow is equivalent to one half the mass of the head times the square of the head's speed at the time of impact <math>(E={mv^2 \over 2})</math>. While the energy delivered to the target increases linearly with mass, it increases quadratically with the [[speed]] (see the effect of the handle, below). High tech [[titanium]] heads are lighter and allow for longer handles, thus increasing velocity and delivering the same energy with less arm fatigue than that of a heavier steel head hammer.<ref>{{cite web |title=DeWalt's Titanium Hammer Killer? |url=http://toolmonger.com/2011/06/15/dewalts-titanium-hammer-killer/ |date=2011-06-15 |author=Cage, Chuck |publisher=Toolmonger |access-date=2013-04-18}}</ref> A titanium head has about 3% [[Deflection (physics)|recoil]] energy and can result in greater efficiency and less fatigue when compared to a steel head with up to 30% recoil. [[Dead blow hammer]]s use special rubber or steel shot to absorb [[recoil]] energy, rather than bouncing the hammer head after impact.