Final answer:
The baseball exerts an equal and opposite force of 350N leftward on the bat, in accordance with Newton's Third Law of Motion.
Step-by-step explanation:
According to Newton's Third Law of Motion, which states that for every action there is an equal and opposite reaction, if a bat exerts a 350N rightward force on a baseball, the baseball is exerting a 350N leftward force on the bat. The magnitudes of the forces are equal, but they are in opposite directions. This is true even when considering the dynamic interaction during the collision where the ball deforms and the force changes over the impact time. The average force during the collision can be used for calculations related to impulse and change in momentum within making connections: baseball physics problems.