Final answer:
The acceleration of a rocket ship in space after engine firing is caused by thrust generated through the ejection of exhaust gases, following Newton's third law of motion, with factors such as exhaust velocity and fuel consumption rate being crucial to the resulting force.
Step-by-step explanation:
The force that accelerates a rocket ship in space when it fires its engine comes from the thrust generated by the ejection of exhaust gases. According to Newton's third law of motion, when the rocket expels these gases at high speed in one direction, a reaction force is generated in the opposite direction, which propels the rocket forward. This reaction force can be further understood using the concept of momentum.
The expelled gases carry momentum away from the rocket, and the conservation of momentum dictates that the rocket must gain momentum in the opposite direction. Moreover, the rate of fuel consumption and the exhaust velocity are critical factors that determine the thrust and hence the acceleration of the rocket. As the rocket's fuel burns and its mass decreases, the acceleration increases because there is less mass to accelerate. This process enables rockets to move more efficiently in the vacuum of space where they do not rely on atmospheric pressure or the Earth's surface to produce motion.