Answer:
The force the rock exerts on Sarah =#is 65 N
Step-by-step explanation:
The given parameters are;
Sarah's weight = 392 N
The force with which Sarah pushes the rock = 65 N
The mass of the rock = 56 kg
The weight of the rock = The mass of the rock × Acceleration due to gravity
∴ The weight of the rock = 56 kg ×9.81 m/s² = 549.36 N
Given that the force Sarah applies to push the rock = 65 N, then by Newton's third law of motion which states that action and reaction are equal and opposite, the force that the rock exert on Sarah is equal an opposite to the force Sarah is applying
Therefore, the force the rock exerts on Sarah = 65 N (in the opposite direction).