Final answer:
The velocity of a fly and the acceleration of gravity are vectors from the list, as they include both magnitude and direction. The others are scalars since they do not have an associated direction.
Step-by-step explanation:
Identifying Vectors from a List
In physics, vectors are quantities that have both magnitude and direction, while scalars have only magnitude. From the list provided, the velocity of a fly and the acceleration of gravity are examples of vectors because they both have magnitude and direction. For instance, the velocity of a fly could be 2.5 m/s north, which specifies the speed (magnitude) as well as the direction (north). Similarly, the acceleration of gravity on Earth is approximately 9.8 m/s² directed towards the center of the Earth.
As for scalar quantities, a person's height, the altitude on Mt. Everest, the age of Earth, the boiling point of water, the cost of this book, and the Earth's population are all examples. They have magnitude but no specific direction associated with them. For example, the height of a person might be 1.75 meters, but it doesn't specify a direction.
To further clarify the concept of vectors, consider the displacement of a person. If someone walks 10 meters east, their displacement is a vector since it tells you not only how far the person went but also in which direction. On the other hand, the distance they walked would be a scalar since it only tells us how far the person went, not the direction.