Final answer:
An astronaut throwing an object while floating in space would move in the opposite direction due to Newton's third law of motion. To prevent recoil of a vehicle in space when an astronaut pushes off from it, reaction control thrusters can be used to counteract the force.
Step-by-step explanation:
When an astronaut, floating at rest in space, throws a massive fire extinguisher away from herself, she will move in the opposite direction. This occurs due to Newton's third law of motion, which states that for every action there is an equal and opposite reaction. When the astronaut exerts a force by throwing the extinguisher, an equal and opposite force is exerted on her, causing her to move in the opposite direction of the throw.
This is a conservation of momentum issue. If we consider exerting a force on the astronaut, such as them pushing off from the vehicle in which they orbit, the vehicle would experience an equal and opposite force. This recoil could affect the measurement of the astronaut's acceleration.
To avoid the recoil effect of the vehicle, one approach would be to use reaction control thrusters on the vehicle that fire in the opposite direction of the astronaut's push. This would counteract the force exerted by the astronaut and maintain the stability of the vehicle's position and orbit while allowing the astronaut to move as desired.