The volume of a spear can be calculated using the formula V = (4/3) x π x (r^3), where V is the volume, π is the mathematical constant pi (approximately equal to 3.14159), and r is the radius of the sphere.
Since the diameter of the spear is given as 15 cm, the radius would be half of that, which is 7.5 cm (or 0.075 meters).
Plugging in the values, we get:
V = (4/3) x π x (0.075)^3
V = 0.00017678 cubic meters
Rounding this answer to the nearest whole number, we get:
V ≈ 0 cubic meters
Therefore, to the nearest whole number, the volume of a spear with a diameter of 15 cm is 0 cubic meters. However, please note that this answer assumes that the spear is a perfect sphere, which may not be the case in reality.