Solving the Spaceship Problem: Comparing Forces

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In summary, the conversation discusses the question of how people in two identical spaceships, one stationary and one traveling at a constant speed, would feel the force or acceleration when the engines start. Some believe that the spaceship with higher initial speed would feel more force, but the expert disagrees and explains that the velocity in the formula is related to the gas emitted by the engines. Ultimately, it is concluded that both spaceships would feel the same force when the engines start at the same time, regardless of their initial speed. This is in line with the principle of Gallilean relativity.
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mrhoneycinnamo
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dear friends, days ago on a physics forum I saw this interesting question regarding fixed power and speed of a spaceship. After thinking for a while I came up with my answer but I am not really sure its correct.So please tell me what you think the answer is.

The question is: imagine there are 2 identical spaceship(with 2 identical engines),1 in stationary state,other travels at constant speed in a straight direction.Now 2 engines starts, how do people in different spaceship feel about the force(or the acceleration)?

some people believe that the one with higher initial speed(lets call it spaceship B) "feels" more force acting on it, becoz of the formula p=fv(since p is fixed, f decreases while v increases).

Somehow I disagree with it.(tell me if i am wrong:))
here is my reasoning:
since the way spaceship's engine works is to utilise the reaction force of its emitted gas(i don't know how to describe it but i assume you understand:)), so the velocity in the formula has something to do with the gas.Since both spaceships A and B was in balanced state, after the engines starts(assuming they start at the same time), A and B would travel at the same accelerating speed at any given time(take their emitted gas as reference frame).since p=fv, f is the same.
so my conclusion is people in both spaceship would feel the same force when the engines start at the same time. If i am wrong about this, please tell me why.
 
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The "one with the higher initial speed" thinks that the other one is the one with the initial speed. Each spaceship thinks that they are the one that is stationary. And so each spaceship uses "v=0" in their own equation.

mrhoneycinnamo said:
so my conclusion is people in both spaceship would feel the same force when the engines start at the same time. If i am wrong about this, please tell me why.

Yes, I believe this conclusion is correct. (I didn't completely follow your reasoning, though.)
 
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"Force equals mass times acceleration". With the same acceleration, the same force will be felt. Initial speed is irrelevant. That goes back to "Gallilean relativity".
 
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1. What is the "Spaceship Problem" and why is it important to solve?

The "Spaceship Problem" refers to the challenge of designing a spacecraft that can travel long distances in space. It is important to solve because as humans continue to explore and potentially colonize other planets, we will need efficient and effective methods of transportation.

2. How do forces play a role in solving the spaceship problem?

Forces are essential in solving the spaceship problem because they are what allow a spacecraft to move and change direction in space. In order to design a successful spacecraft, scientists must understand and compare the different forces acting on it, such as thrust, gravity, and air resistance.

3. What are some common forces that act on a spacecraft?

Some common forces that act on a spacecraft include thrust from engines, gravity from celestial bodies, and air resistance from the surrounding environment. Other forces, such as solar radiation and magnetic fields, may also have an impact on a spacecraft's journey.

4. How do scientists compare forces when solving the spaceship problem?

Scientists compare forces by using mathematical equations and models to analyze and predict how they will affect a spacecraft's movement. They also conduct experiments and simulations to test different designs and determine the most efficient methods for dealing with these forces.

5. What are some potential solutions for overcoming the forces in the spaceship problem?

Some potential solutions for overcoming the forces in the spaceship problem include using more powerful engines for greater thrust, using gravitational slingshots to conserve fuel, and designing spacecrafts with aerodynamic shapes to reduce air resistance. Other solutions may involve utilizing new technologies, such as solar sails or ion propulsion, to propel a spacecraft through space.

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