What is a forward pass?

[Not a jock]

One of the current threads mentioned "forward passes". It prompted me to take a look at the laws etc on the World Rugby website.

It contains the definition: "Forward: Towards the opposition’s dead-ball line." That's clear, isn't it?!

To digress for a moment, there's been much debate recently about the aspirations for a significant improvement in our Maths skills. I recall a Maths question something like this: If a person who can swim at 1 m/s enters a river that's flowing at 2 m/s and is 10m wide, where will they end up if they swim directly towards the opposite bank? If the river is flowing at 0.5 m/s in what direction do they aim in order to reach the opposite bank level with their starting point and how long will it take them to reach the bank?" What's this got to do with forward passes? Well, it's all about vectors and relative velocities.

A winger might be running flat out at close to 10 m/s. They might pass it to the overlapping fullback who might also be running at close to 10 m/s (if he's a young Hogg). If they're 5m apart, the ball will take a finite time to reach the FB during which time its motion relative to the ground will be a vector combining the players' motions and the pass. As a result the pass may be forward relative to the ground (and opponent's deadball line (see definition above)) but not relative to the FB.

I'm sure I've heard refs comment on hand direction being flat or backward when delivering a pass so they tend to favour allowing passes tha are forward relative to the ground but that are backward relative to the receiving player. I tend to agree that this makes sense and is easier to judge but it doesn't seem consistent with the laws. Have I interpreted this correctly?

[Rugbygramps]

Certainly one of the main criteria seems to be the direction that the ball leaves the hand. So if it leaves the hand backwards, or even level, but ends up in front of the passer then that is deemed ok.

For me it should simply be if the ball ends up further forward than the position it was passed from then it’s a forward pass. SIMPLES

[BigChris]

Ive always used this video as my main point of reference....

https://www.youtube.com/watch?v=box08lq9ylg

[wigworth]

For me it should simply be if the ball ends up further forward than the position it was passed from then it’s a forward pass. SIMPLES

This, anything else is superfluous fluff that doesn't need to be there.

[Hot_Charlie]

For me it should simply be if the ball ends up further forward than the position it was passed from then it’s a forward pass. SIMPLES

This, anything else is superfluous fluff that doesn't need to be there.

Yep. Sadly World Rugby decided to become physics experts. I suspect the original calls and lobbying for this probably came from NZ as obviously it suits their tradition of free-flowing, fast paced rugby.

[ay2oh]

If the receiver catches the ball in front of where it was passed it’s forward. End of.

[Nofrontteeth]

If the receiver catches the ball in front of where it was passed it’s forward. End of.

Agree. As kids drummed into us "if it isn't backwards it forward". Flat passes were scourned as potential ball loss. Especially if the scrum was under pressure.

Another by-product of the "got to be faster, score more and 'entertain" idiom, much stemming from the southern hemisphere.

[Not a jock]

Ive always used this video as my main point of reference....

https://www.youtube.com/watch?v=box08lq9ylg

BigChris, thanks for posting the link to the IRB video - that's a much better description of the issue than my rambling post. It seems that the IRB's definition of forward is at odds to that of the others responding to my post. I particularly liked the example of the pass over the head to the player behind that actually moved forward relative to the ground. Who thinks that's a forward pass????

If IRB/WR support this interpretation, they should make it clear in the laws.

[Tykger]

I thought that they were putting a gadget in the ball to determine whether it was passed forward.if so,they will have to decide the criteria. Wasn't the same tech going to be used to determine where the ball crossed the touchline ???

[Old Hob]

I thought that all this had been decided. First of all, the entire Crumbie stand will tell you when it's forward, and generally they are right. However, the ball will travel forward from the hand of the passer at the same speed as that of the passer, however, this momentum will dissipate. Forward is therefore defined as relative to the players not the pitch, otherwise all passing would have to be done while stationary.

[Old Hob]

Perhaps an extreme example would help:

You are in a goods van of a train travelling at 60mph. Everything in the van is therefore also going at 60 mph. You pass the ball from the front left corner of the van to a colleague in the rear right. That is obviously a legal pass but the ball, relative to the ground, was travelling forward at 60mph minus the speed of your pass. Now, a player's running speed will obviously be lower but the principle is the same.

[Not a jock]

I thought that all this had been decided. First of all, the entire Crumbie stand will tell you when it's forward, and generally they are right. However, the ball will travel forward from the hand of the passer at the same speed as that of the passer, however, this momentum will dissipate. Forward is therefore defined as relative to the players not the pitch, otherwise all passing would have to be done while stationary.

I don't agree with your comment about being stationary is necessary to have the ball's motion relative to the pitch to be not forwards.

As the ball leaves the player's hands, it's motion has two parts. One due to the player moving and one due to the pass itself. Let's call the player's movement the x-direction. If the x-direction component of the pass is negative with a greater magnitude than the player's motion, it will travel backwards relative to the ground. (over short distances we can ignore drag from the air and gravity - unless it's a J Allen dive pass).

In the IRB video example the ball moves forward approximately 2m relative to the pitch even though the passer is always in front of the reciver. If passed more than 2m "back" say the receiver were 3m behind the passer, it would travel bacwards relative to the pitch.

[Rugbygramps]

There are some excellent examples given, the problem is Stephen Hawking isn’t always available when you need him.

I get the science but it’s just another example of things bing over complicated

[Nofrontteeth]

Perhaps an extreme example would help:

You are in a goods van of a train travelling at 60mph. Everything in the van is therefore also going at 60 mph. You pass the ball from the front left corner of the van to a colleague in the rear right. That is obviously a legal pass but the ball, relative to the ground, was travelling forward at 60mph minus the speed of your pass. Now, a player's running speed will obviously be lower but the principle is the same.

Ahh schooldays and Einstein's relativity

What happens to this scenario if, as some would want the game is played at the speed of light?

[TigerFeetSteve]

Perhaps an extreme example would help:

You are in a goods van of a train travelling at 60mph. Everything in the van is therefore also going at 60 mph. You pass the ball from the front left corner of the van to a colleague in the rear right. That is obviously a legal pass but the ball, relative to the ground, was travelling forward at 60mph minus the speed of your pass. Now, a player's running speed will obviously be lower but the principle is the same.

Ahh schooldays and Einstein's relativity

What happens to this scenario if, as some would want the game is played at the speed of light?

Then the mass of the player would be infinite, so it would by definition become impossible to stop Jasper.