Final answer:
The normal force of the elevator floor on a 5.0 kg dog in an accelerating elevator is 43 N. The force that the dog exerts on the elevator floor is also 43 N, following Newton's Third Law of Motion.
Step-by-step explanation:
Normal Force on a Dog in an Accelerating Elevator:
The normal force on an object represents the force perpendicular to the surface it is in contact with. For a 5.0 kg dog sitting in an accelerating elevator going downward, the normal force can be found by subtracting the force due to acceleration from the gravitational force. The gravitational force (weight) on the dog is the product of its mass and gravitational acceleration (approximately 9.81 m/s²), which amounts to
5.0 kg × 9.81 m/s² = 49 N. The force due to the elevator's acceleration is 5.0 kg × 1.20 m/s² = 6 N. The normal force is therefore 49 N - 6 N = 43 N. As for the force the dog exerts on the elevator floor, it is equal to the normal force exerted on the dog by the floor, due to Newton's Third Law of Motion, so it is also 43 N.
The answer choices provided in the question would suggest Option B: 43 N for both the magnitude of the normal force of the elevator floor on the dog and the force the dog exerts on the elevator floor.