This First assumption being made for this example is that the gloves have no weight. This is not a bad assumption because compitition gloves weigh only 8 ounces and don't provide much cushoning.

So, the weight in this equation is limited only to the arm of the boxer. If we assume that each arm is 7% of the body weight, that means the punch has roughtly 14 pounds or 6.5kg of force behind it.

A jab is the fastest of the punches. We assume the punch goes from puncher to punchie in 1/5th of a second. Since the arm travels roughly 18 inches, that means the punch is traveling roughly at a speed of 7.5 feet/sec or 2.3m/s.

Starting at rest and accelerating to 2.3m/s in 1/5th of a second means the arm has an acceleration if (2.3m/s - 0m/s)/.2s = 11.5m/s².

Next, if we assume that the opponents head is a stationary object absorbing all the force of the impact, The force on the opponents head can be modeled as:

    6.5kg * 11.5 m/s² = 75N

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