 
Thought for the Week
By Ed Hall, NiDan
Titusville Karate Dojo
Momentum
The dictionary defines momentum as: the motion of a body equal to the product
of its mass and velocity. Let us say the arm has a mass of 10 pounds. By
standing still and striking at a velocity of 40 feet per second, the total
momentum will be 400 ftlbs./sec (10 times 40). On the other hand, let us
say the body has a mass of 170 pounds. By stepping in and striking at 40
feet per second, the total momentum will be 6800 ftlbs./sec (170 times 40).
In the second case, the whole body is used as the strike. The difficulty
in achieving this ideal is that we must step first. We can't just pick up
the whole body and throw it at the target, the body must arrive at the target
still standing and in control. The phrase we hear constantly is "Step first,
then punch". Upon first learning, the timing of this shift is a twopart
move  1) step 2)punch. Because of the pause, the momentum drops back down
to, at maximum, 400 ftlbs./sec. With years of practice, the timing of the
transition of "stepthenpunch" becomes fluid. Only then can we come close
to maximum momentum. Carrying the case one step further, lets us say the
attacker's body has a mass of 170 pounds, and he attacks at a velocity of
40 feet per second. By sidestepping in and counterattacking at the same
velocity the momentum becomes 46,240,000 ftlbs./sec ! (170 times 40 times
170 times 40). Obviously, these are ideals, not correcting for gravity or
friction and assuming the total transfer of momentum to the target, which
is impossible.
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