Newton (unit)

A newton (N) is the force that gives a mass of 1 kg an acceleration of 1 m/s²:

$$1\ \text{N} = 1\ \text{kg} \cdot \text{m/s}^2$$

Gravity on Earth pulls with $g \approx 9.81$ N on each kilogram. So a mass $m$ weighs $F = m g$:

$$77\ \text{kg} \times 9.81\ \text{m/s}^2 \approx 755\ \text{N}$$

Some forces for scale

force	roughly
10 N	holding a 1 kg bag of sugar
50 N	a firm poke
600 N	the weight of a 61 kg person
860 N	the weight of an 88 kg person: more than the fighter’s own weight

Impulse

How much a shove moves a body depends not only on its force but on how long it lasts. Force times time is the impulse, and it equals the change in momentum:

$$J = F\,\Delta t = m\,\Delta v$$

A brief 860 N shove for 0.15 s has an impulse of about 130 N·s. On a 77 kg body that’s a change in speed of about 1.7 m/s.

In this project

Shove forces are given in newtons. They range from 30 N up to a top force set by the curriculum, $F_{\max} = 80 + 520 \cdot \text{level}$: 600 N at level 1.0 and 860 N at level 1.5 (see push recovery).