An unanchored 3-D portable archery target made of foam can withstand a 20
to 150-pound blow from an arrow without tipping completely over even
though the target's weight (e.g., about 10 lbs.) is less than the arrow's
force of impact. To achieve such surprising and unexpected results, the
target employs a unique combination of weight, foam density, and a center
of gravity that is counter-intuitively elevated to provide the target
with a greater rotational moment of inertia. Although it would seem that
an arrow with 800 in-lbs of kinetic energy should be capable of
completely tipping over a target that requires only about 15 in-lbs of
energy to tip over, the target's foam core has a density and gumminess
that quickly dissipates most of the arrow's kinetic energy before the
energy has time to tip the target over. A hollowed-out base underneath
the target provides the target with greater stability.