[Bored chemist]

Next , I already stated that the recoil is 1 pound average , same as a 1GW laser . 

And I showed why you are wrong by about 4000 fold

You aren't getting how it functions , and it's results . 

You have been unable to show us.
You have made claims, but they might as well have said it works by magic.

A baseball with 1GJ energy is heavy artillery ! 

Yes.
As I said

The peak forces would be tricky. :-)

If you can't even envision this simple of a mechanical system , you are NOT qualified to  criticize me !

I can envision it and, unlike you , I can calculate what would happen in reality (rather than in your pipedreams).
It doesn't work.
And I have explained why- I even gave you an example (repeatedly) which you didn't understand because...

you are NOT qualified to  criticize me ! 

Formulas are just a descriptor , NOT a concept !

Stop pretending that "concepts" are all that important.
I can conceive of a thing that makes you understand these problems.

But my imagining it doesn't make it happen.

[Professor Mega-Mind (OP)]

.................Tough Logic .
Last time I lifted the lid , you were claiming that an average output of 1GW didn't have a 1lb recoil , alternatively , you were claiming that transferring that energy to the stream of baseballs wouldn't result in a 1GJ per second artillery-base ball impact . 
I think you barfed up your word-salad here !
P.M.

[Bored chemist]

Last time I lifted the lid , you were claiming that an average output of 1GW didn't have a 1lb recoil

In the case of a GW laser the recoil is about a pound.
But you can't use a GW laser to accelerate a bunch of billiard balls to 1GW because (as explained before) roughly half the ball comes back at you.
Essentially, the ball explodes equally in all directions even though you only hit it from one side (strictly speaking it gets pushed away from the laser by about a pound of thrust but since it's exploding at the time that's hardly noticeable).

I think you barfed up your word-salad here !

Not, it's the usual problem. You don't understand and yet you think that the problem is the two scientists telling you how things really work.

[Professor Mega-Mind (OP)]

..................Too literal .
To complete the ANALOGY , take the energy contained in the "magic" ray (1GW) , change it into kinetic energy , concentrating 1GW sec in each billiard ball .  What happens when those balls "artillery" strike the brick house ?
P.M.

[Kryptid]

I'm still waiting for clarification on my questions.

[Professor Mega-Mind (OP)]

Might be a while 'till I give myself a headache .  Meanwhile , just for shirts and grins , why don't you answer for b.c. above ?
P.M.

[Kryptid]

Meanwhile , just for shirts and grins , why don't you answer for b.c. above ?

Assuming billiard balls that are indestructible (because, as Bored Chemist said earlier, a gigawatt laser would not be kind to real ones), you'd get a gradual acceleration of the balls. To simplify this, we'll assume one ball. If all of the laser light hits and deflects off of the ball back the direction it came, then that ball is pushed with a force of about 3.3356 newtons (0.75 pounds). Using Bored Chemist's earlier figure of 0.17 kilograms for the mass of the ball, we can compute acceleration from force divided by mass. 3.3356 newtons divided by 0.17 kilograms equals an acceleration of 19.62118 meters per second squared.

You want the ball to have a final kinetic energy of 1 gigajoule. For an object with a mass of 0.17 kilograms, that would require a velocity of 108,465.2 meters per second: https://www.omnicalculator.com/physics/kinetic-energy

At an acceleration rate of 19.62118 meters per second squared, it would require 5,527.97 seconds (1.536 hours) to reach that speed and cover a distance of 299,796 kilometers in the process (I hope you were performing this experiment in space: https://www.omnicalculator.com/physics/acceleration

 During those 1.536 hours, the laser has expended a total 5.52797 terajoules of energy. So yes, a billiard ball with a kinetic energy of 1 gigajoule is going to be devastating to a house, but look how long it takes to build it up to that speed and how much total laser energy is required.

[Professor Mega-Mind (OP)]

Dooood !
 Macro-physics won't work here !  I spent over 5 years chasing that wild goose !  To mimic micro-physics you must assume that 99% of the photonic-rocket energy is translated into the kinetic energy of the ball .  This is what H.E.X-rays do to electrons .  The power of the impact that you calculated would happen with every ball , once a second .  Acceleration would be almost instantaneous . 
 Now , run it again properly , then congratulate me on my triumph !
P.M.

[Kryptid]

Dooood !
 Macro-physics won't work here !  I spent over 5 years chasing that wild goose !  To mimic micro-physics you must assume that 99% of the photonic-rocket energy is translated into the kinetic energy of the ball .  This is what H.E.X-rays do to electrons .  The power of the impact that you calculated would happen with every ball , once a second .  Acceleration would be almost instantaneous . 
 Now , run it again properly , then congratulate me on my triumph !
P.M.

You said billiard balls specifically, so I used the physics relevant to billiard balls. If you wanted electrons, you should have said electrons. Make up your mind.

Okay, so what if we do have a billiard ball's mass of electrons instead? If the mass of an electron is 9.10938356 x 10^-31, then 0.17 kilograms would amount to 1.866 x 10²⁹ electrons. I'll use my earlier calculations to simplify this. I already calculated that an X-ray laser which has a photon energy of 10 MeV produces 6.2415093 x 10²⁰ photons per second. If each photon hits one electron, then the time required for 1.866 x 10²⁹ electrons to be accelerated by photons coming in at a rate of 6.2415093 x 10²⁰ photons per second is 298,966,149 seconds (9.48 years).

So after 9.48 years, all of the electrons have been accelerated to 299,420,537 m/s (99.876% c) inside of an extremely long tube of some kind. Since we know that the number of electrons flowing past a given point in the tube is equal to the rate that the laser produced the photons, we can use my previous calculations to determine that the mass flow rate is (6.2415093 x 10²⁰ electrons per second) x (1.829337 x 10^-29 kg relativistic electron mass) = 1.14178239 x 10^-8 kg/s. With the mass flow rate known, the thrust is calculated as (299,420,537 m/s electron speed) x (1.14178239 x 10^-8 kg/s) = 3.4187 N (0.768 pounds). This is, of course, exactly the same as my initial calculations.

Since the first electron was accelerated 9.48 years before the last one, then the electron stream will impact the receiver with a force of 3.4187 newtons over a period of 9.48 years. You want all of the electrons to be accelerated at once, but the problem is that there simply aren't enough photons coming in fast enough to get the job done. You could get more photons either by lowering the energy available for each photon while keeping the laser power constant (which will make each electron move slower) or you can increase the total power of the laser instead.

If you want all 0.17 kilograms (1.866 x 10²⁹) of electrons to be accelerated to 99.876% the speed of light in one second, then the laser will need to provide 10 MeV photons at a rate of 1.866 x 10²⁹ per second. That requires a total laser power of 298,966,149 gigawatts.

[Bored chemist]

take the energy contained in the "magic" ray (1GW) , change it into kinetic energy ,

This is the stage at which a reaction force is generated.

What happens when those balls "artillery" strike the brick house ?
P.M.

Who cares?
It's not a reactionless drive so it's off topic.

[Bored chemist]

Acceleration would be almost instantaneous . 

Acceleration requires a force and that, in turn, requires a reaction thanks to Newton's laws.

 Macro-physics won't work here !  I

Why not?
(If you think the answer is "quantum" then you don't understand the question.)

I spent over 5 years chasing that wild goose !

It's a pity you didn't spend 5 weeks studying physics.

then congratulate me on my triumph !

Your ability to let your imagination over-rule logic isn't a triumph.

[Professor Mega-Mind (OP)]

...................Blind Guys !
So solly to see you sprain your brains unnecessarily !  You don't need to make it that complicated , just dump in enough electrons to absorb the X-ray's energy , and you will get a 1GJ impact at the target . It's a simple logic exercise , light cannot impact effectively , electrons can .  The practical details will be learned through experience , the basic design is what is important at this point .  So you see , the creative mechanical designer SPANKS the rediculous number crunchers yet again !
P.M.

[Kryptid]

...................Blind Guys !
So solly to see you sprain your brains unnecessarily !  You don't need to make it that complicated , just dump in enough electrons to absorb the X-ray's energy , and you will get a 1GJ impact at the target . It's a simple logic exercise , light cannot impact effectively , electrons can .  The practical details will be learned through experience , the basic design is what is important at this point .  So you see , the creative mechanical designer SPANKS the rediculous number crunchers yet again !
P.M.

You're completely glossing over my refutations. Again. You asked me to do redo the calculations for electrons and I did. The least you could do is respect my efforts and actually directly address what I've said. If my set-up does not reflect the function of your engine, then point out specifically which step I got wrong. I'm getting close to giving up on you.

[Professor Mega-Mind (OP)]

...............Barney Google
Doodo , your calc.s are misguided .  I will simplify this down to baby food for you .  A 1GW photonic rocket is fired at a target .  It produces 3/4 lbs of thrust , and 1.5 pounds recoil upon reflection from the target .  A steady stream of electrons is then injected into the rocket ; one electron per H.E.X-ray .  The resultant electron stream now has .99 GW of kinetic energy , the EMR reflected backwards has the remaining 1% .  When the electrons  strike the target , they will impact it , unlike light , which bounces off uselessly .  This will release 1 GJ of kinetic energy into the target each second .  That is equivalent to one stick of dynamite exploding against the target every milli-second !  I say that the target is propelled far more powerfully than the rocket , ergo : Difference Engine !
If you can't envision this , then I can't fix what's wrong .  Maybe a Total Recall-style memory implant !
Oh , and don't hold your breath , waiting for me to go Dr. Gunter Zoloff .  That is NOT happening !
Tarzan Yell .
P.M.

[Bored chemist]

...................Blind Guys !
So solly to see you sprain your brains unnecessarily !  You don't need to make it that complicated , just dump in enough electrons to absorb the X-ray's energy , and you will get a 1GJ impact at the target . It's a simple logic exercise , light cannot impact effectively , electrons can .  The practical details will be learned through experience , the basic design is what is important at this point .  So you see , the creative mechanical designer SPANKS the rediculous number crunchers yet again !
P.M.

OK, let's see if I can get you to understand the root of the problem
You have a billiard ball flying through a big vacuum chamber at a few m/s - someone (in a space suit) threw it. Nothing complicated or relativistic.
It's the black ball and so it absorbs light really well.
I have a video camera pointed at it and hooked to a computer.
The centre of the ball is following a parabola and the computer is programmed to track the ball and work out the path  followed by the centre of the  ball so it can work out where the ball will go.

Now imagine that I fire a high power laser pulse at it and the light is absorbed by the ball.
The side of the ball nearest me  instantly boils.

 ( the computer now has a more difficult job because half the ball is now a cloud of hot gas + smoke).

What happens to the track of the centre of the ball?

BTW, I'm going to keep asking that question until you actually answer it.

[Bored chemist]

I will simplify this down to baby food for you .

What you have done there is more akin to turning it into what baby food becomes after going through the baby.

[Professor Mega-Mind (OP)]

If I can add 1GJ KE to the baby's ejecta , it'll launch too !
P.

[Bored chemist]

What happens to the track of the centre of the ball?

BTW, I'm going to keep asking that question until you actually answer it.

[Professor Mega-Mind (OP)]

It's an irrelevant question , since light does not boil electrons , it just impacts and throws them .
P.M.

[Bored chemist]

since light does not boil electrons

The process is called photoionisation.

What happens to the track of the centre of the ball?

BTW, I'm going to keep asking that question until you actually answer it.