Misinterpretation of the KnockOn/Forward Pass

Misinterpretation of the KnockOn/Forward Pass

Post by Peter Davie » Tue, 11 Mar 1997 04:00:00

Yesterday during the Canberra v Penrith game the ref ruled a
scrum for a knock on. In answer to complaing Canberra players
the wired ref was heard to say "the ball was propelled forward"
when it most obviously was not. This confirmed for me what I
have long suspected, that the refs and officilas are confused
about relative velocity and acceleration.

Propel according to the dictionary means "drive forward" or
"give forward motion". (They didn't need to add forward)
The measure of motion is velocity which has magnitude and
direction. The rate of change of velocity is acceleration.

When a pass is thrown with backward direction but floats
forward due to the momentum of the passer the pass is said
to go backwards relative to the players velocity. If the
player receiving the ball deflects it and has no or little
velocity then how can a ball which moves back be deemed to
be propelled forward.

This is what happened yesterday, the ball travelling back
was deflected (or accelerated) forward but was still in
backward motion. The ball was not propelled forward but
accelerated forward. This, for example, is what happens
when a person knocks on but the ball travels thru their
legs. The referee rules a knock on despite the ball
still moving back away from the defenders line.

If the officials want to keep pulling up knock backs
for scrums they should change the wording of the rule
to say 'accelerated toward the opponents goal line'
but it's no good to persist with this misunderstanding.
If we're going to take this game to the world it
would not be best to confuse potential consumers with
a misunderstanding of simple Newtonian Mechanics. It
doesn't look good to hear a ref say "propelled forward"
when it isn't.

Peter Davies