Final answer:
The normal force exerted by a 20.5 kg box on a 9.30 kg box, on a horizontal surface with no vertical acceleration, is equal to the weight of the 9.30 kg box, which is 91.14 N. The given options do not accurately reflect this calculation.
Step-by-step explanation:
The question asks to determine the normal force that a 20.5 kg box exerts on a 9.30 kg box when they are in contact on a horizontal surface and not accelerating vertically. To find this normal force, we use the concept that the normal force is equal to the gravitational force acting on the 9.30 kg box if the boxes are not accelerating vertically.
The gravitational force (weight) of the 9.30 kg box is calculated using the equation Weight (W) = mass (m) × acceleration due to gravity (g), where g is 9.8 m/s². Therefore, the normal force exerted by the 20.5 kg box on the 9.30 kg box is equal to the weight of the 9.30 kg box:
Normal Force (N) = m × g
N = 9.30 kg × 9.8 m/s²
N = 91.14 N
So the answer that best fits this calculation is not in the provided options, and there seems to be a mistake in the given multiple-choice options. The normal force that the heavier box exerts on the lighter box is 91.14 N, assuming there are no other vertical forces acting on the lighter box (such as an applied force or additional weight).