# Physics of Blocks

As you reduce the distance between yourself and your opponent, the impact you feel when blocking an attack is reduced. This may be explained by a formula for linear velocity as it relates to angular velocity.

Angular velocity is simply the speed that a rigid object takes on as it rotates about a fixed point. For example, in a Taekwondo round kick, assume that the leg (rigid object) rotates from the hip (the fixed point). The formula for angular velocity is defined as follows:

a = 0 / t

Where "0" represents the angle of rotation and t represents the time taken to rotate through that angle. The units for angular velocity could be in degrees per minute or rotations per minute or, more appropriately for the kicker, in degrees per second. Angular velocity has a direct relationship with the angle of rotation. If the kick is allowed to accelerate through a greater rotation, it will damage the target more when it makes contact with it. If the blocker anticipates and side steps into the kick's path, the angular speed of the leg is reduced and thus the impact of the leg is reduced.

Linear velocity, as it relates to its angular velocity counterpart, is the speed of any point on the rotating body, and is proportional to the radial distance from the center to that point. Think about cracking a whip. The speed at of the handle is relatively slow while the tip moves so fast it snaps. The formula for linear velocity is defined as follows:

v = a x r

Where "a" is the angular velocity as before. If you decrease the distance r between the rotating leg that is attacking, the speed at which it hits you is reduced. Thus, reducing the distance between you and your opponent will reduce the kick's impact.