Final answer:
The magnitude of the downward force on an object is its weight. For an object with a mass of 73 kg, the weight would be 716.33 N by multiplying the mass by the acceleration due to gravity (9.81 m/s^2).
Step-by-step explanation:
The question is asking about the magnitude of the downward force on a section labeled as 'A'. To answer this, we refer to Newton's second law, which states that the net external force on an object is the product of its mass (m) and its acceleration (a), that is, Fnet = ma. In the context of an object falling towards Earth, the only force acting on it is its weight, which is the product of its mass and the acceleration due to gravity (g). Hence, the magnitude of the downward force on an object is equal to its weight, w = mg.
For instance, consider an object with mass m = 73 kg. The force of gravity acting on it, or its weight, would be w = m × g, where g is approximately 9.81 m/s^2 on the surface of the Earth. Therefore, the weight of the object, which is the magnitude of the downward force, would be 73 kg × 9.81 m/s^2 = 716.33 N (Newtons).
In a case where other forces are mentioned, such as in the provided information where force magnitudes are given as 10.5 N, 833 N, and force components are described in a scenario with 100.0 N horizontal components, the overall downward force on 'section A' must take into account all forces acting in the downward direction, including weight, friction, and any other relevant forces.