Final answer:
The 4.5-N object will float in glycerin because the buoyant force exerted on it is 5.0 N, which is greater than the object's weight.
Step-by-step explanation:
When a 4.5-N object is placed in glycerin and the glycerin exerts a buoyant force of 5.0 N on the object, the object will float. This is because the buoyant force exerted by glycerin on the object is greater than the object's weight. The principle that explains this behavior is known as Archimedes' principle, which states that the upward buoyant force on a submerged object is equal to the weight of the fluid that the object displaces. If the buoyant force is greater, the object rises and floats; if it is less, the object sinks.