Final answer:
The action-reaction pairs of forces for the apple and the Earth and for the apple and the hand are described using Newton's third law of motion. The mass of the Earth can be found using the equation F = ma, where F is the gravitational force, m is the mass, and a is the acceleration due to gravity.
Step-by-step explanation:
(a) According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In the case of the apple and the Earth, the action-reaction pairs of forces are: the Earth exerts a gravitational force on the apple, and the apple exerts an equal and opposite gravitational force on the Earth. Similarly, for the apple and the hand, the action-reaction pairs of forces are: the hand exerts an upward force on the apple, and the apple exerts an equal and opposite downward force on the hand.
(b) To find the mass of the Earth, we can use the equation F = ma, where F is the gravitational force, m is the mass, and a is the acceleration due to gravity. Rearranging the equation, we get m = F / a. Substituting in the known values (force = mass × acceleration), we have m = (0.444 kg × 9.8 m/s²) / 9.8 m/s² = 0.444 kg.