Which generates more force? An open-palm or back-handed (b*tch) slap?

Question

I would think an open palm since your using your pectoral muscles and have a greater range of motion, thus generating more power. Though the classic back-hand employs the use of a non-flexed wrist and also is seen more in popular culture as the marquee technique to knock someone down, not to mention the embarrassment factor of being back-handed.

Answer 1

Assuming we can swing either way with the same velocity and put the same amount of mass behind that velocity, there would be no difference.

Force comes from the change in momentum, p = mv, over time. In math talk, we have dp/dt = d(mv)/dt = m dv/dt = ma...our old friend f = ma. The mass, m, would be whatever mass you can put behind either slap. That is, whatever is put into motion in the direction of the momentum.

If you think M > m where M is the mass behind the open palm slap and m is the backhanded one, and if the two velocities are equal V = v, then the open palm slap would generate more force.

But often the energy required to get a mass M > m moving at the same acceleration and end velocity is too great. So if your slapper is not particularly strong, the open hand slap, with greater M behind it, might be at a slower velocity than the backhand; so V < v.

So the answer to your question is...it depends. How much mass can the slapper get behind each type of slap and how much velocity can be generated for each type.

By the way, your flexed wrist does have a bearing on the outcome. If the wrist flexes, the mass behind the slap is reduced because it is no longer traveling at the velocity of the slap. In math talk, assume MV is the momentum of the loose wrist slap, upon the moment of impact, some of that M is lost because the wrist flexes and the arm mass and such are out of the picture now. So the hand is the only mass in the impact at mV where m < M.

In boxing, the coach always insists the boxer put his body weight (M) behind all the punches. That's because the arm swing alone gives mV, but with the body into the punch, at same velocity, we have (m + M)V and the change in that momentum, the force, is way greater than mV alone.

Answer 2

MY GUESS IS A CLOSED FIST,IT SEAMS TO ME THAT THE MASS BEING IN A TIGHTER AREA WOULD BE
DIRECTED TO A SPECIFIC AREA WITH MORE FORCE

AN OPEN HAND WOULD SPREAD THE ENERGY OVER
A LARGER AREA DISSIPATING THE ENERGY

A BULLET WON T GO THROUGH A B/PROOF VEST
BUT A ICE PICK WILL AT A LOWER VELOCITY