Final answer:
The magnitude and direction of the average force exerted by the bat on the baseball is zero.
Step-by-step explanation:
The average force exerted by the bat on the baseball can be determined by using Newton's second law of motion, which states that the force exerted on an object is equal to its mass multiplied by its acceleration. In this case, the mass of the baseball is given as 150 g (or 0.15 kg) and the time of contact with the bat is given as 20 ms (or 0.02 s).
To find the acceleration, we can use the equation for average acceleration, which is the change in velocity divided by the time taken. The initial velocity of the baseball in the -x direction is 80 mi/h, and after the collision, it moves in the +x direction with the same velocity. Since the change in velocity is zero, the average acceleration is also zero.
Therefore, the magnitude of the average force exerted by the bat on the baseball is zero. Since the force is zero, we can say that the direction of the force is also zero.