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#### s_shrum

**Multiheaded monster...Force, acceleration and the speed of light.**

Me and my long time friend have been fighting over this for too long and can never seem to get together to head over to the College to get a prof. to settle this.

I am looking for:

1) Answers.

2) Practical ways of explaining them

There are two problems (plus one more that I will add in for the theorists in the crowd) so I will throw them out 1 at a time and list my and my friends conclusions. Please tell me if one of us is right (or if we are both wrong) and if you can, please provide your reasoning.

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Question 1:

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GIVEN:

An object or thing (like a child on roller skates) is producing a force that moves that object 10 mph

GIVEN:

a small propulsion device (like a roman candle) that produces a force that moves it 2 mph

TEST CASE:

Strap the roman candle to the moving child ;-) not for real this is all hypothetical.

QUERY:

If an obect (the child) has a force greater then the propulsion (the roman candle), does the force of the propulsion:

a) do nothing to the total force; neither decrease or increase

b) add to it.

My answer: Add to it

My reasoning: Because force, regardless of its multiple sources, is additive when acting as propulsion (or subtract from it if acting against an object as resistance).

My friend's answer: Do nothing

His reasoning: Because the propulsion force is less then the objects force, there will be no effect

Your answer: __________________________

Your reason:___________________________

QUESTION 2:

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Disregarding fuel weight, gravity of large planets, black holes, etc, let's set up a hypothetical scenario...in the empty void of space...

GIVEN:

A rocket ship is standing in space at 0mph (P0). It then produces a propulsive blast (B1) that causes the speed of the rocket to begin traveling from a dead stop (speed = 0) to a speed of 10mph.

GIVEN:

A week later, a 2nd *equal* blast (B2) is produced (I'll call this point in space P1).

What will the speed of the rocket be after the second blast in relation to P0:

a) 10mph

b) greater then 10mph

My answer: B - Greater then 10mph

My reasoning: The effects of the second blast provides a force which (based on my answer to the previous question) is additive. I conceed that the final speed may not be 20mph but will still add some additional speed to the rocket.

My freind's answer: A - 10

His reasoning: Becuase the blast is equal, the force output will be equal to the speed that the rocket is moving at and therefore will have no effect.

Your answer: __________________________

Your reason:___________________________

THEORY QUESTION 1:

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Is it possible to travel faster then the speed of light

a) no

b) yes

My answer: YES but... :-) My answer is based on my inital V-zero starting point (say Earth). I say that it is possible to obtain and pass the speed of light *c* based on the speed I am traveling away from my *original* V-zero starting point. As I pass the speed of light, those persons left behind at the V-zero starting point (Earth), will only see my traveling away UP TO the speed of light, even though my ship (and me in it) are traveling faster then light in relation to them (based on Einstein's law of addition). I conceed that I, in my ship, will never go faster then the speed of light as the speed of light is constant BASED ON MY RELATION TO THE LIGHT.

My Friend's answer is NO...just because nothing can go faster then the speed of light.

Your answer: __________________________

Your reason:___________________________

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I know this is kinda lengthy but I need to put an end to this mess...my friend is easily frustrated and it is driving me nuts that I can't get him to comprehend the difference between acceleration and speed.

TIA

Sean Shrum

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