Final answer:
If an unbalanced force pushed from the back of a spacecraft like Sputnik I, the spacecraft would accelerate further in that direction. The astronaut inside could redistribute force or use thrusters to avoid vehicle recoil. If an astronaut were motionless and needed to move within the ISS, they could throw an object in the opposite direction to propel themselves.
Step-by-step explanation:
When Sputnik I was placed into orbit, the forces affecting it were balanced. If an unbalanced force were applied pushing from the back of the spacecraft, in the same direction it is already moving, this would cause the spacecraft to accelerate further in that direction. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
Exerting a force on an astronaut would mean the vehicle in which they orbit experiences an equal and opposite force, which would affect the astronaut's acceleration. To prevent the recoil of the vehicle, one could design a mechanism to distribute the force evenly or use thrusters strategically placed to counteract the recoil.
If an astronaut in the International Space Station (ISS) needed to move but was out of reach of any solid object, they could do so by throwing an object in the opposite direction they wish to move. Thanks to the conservation of momentum, the astronaut would experience a reaction in the opposite direction, allowing them to move. This is key to understanding the physical concept of action and reaction.