The formula for calculating the volume of plastic pepper balls, whether hollow or solid, is the same, but the formula for calculating the weight is completely different, because the density of plastic solid pepper balls is completely different from that of hollow plastic pepper balls, so the formula for calculating the weight is also different.

V=(4/3)πr^3(1) The generalized concept of plastic pepper ball: The set of points whose distance to a fixed point in space is equal to or less than a fixed length is called a sphere, which is called a ball for short. (Defined from the perspective of set)

(2) Take the straight line where the diameter of the semicircle is located as the rotation axis, and the rotating body formed by the semicircle surface rotating once is called a solid sphere, or ball for short. (Defined from the perspective of rotation)

(3) Take the straight line where the diameter of the circle is located as the rotation axis, and the rotating body formed by rotating the circular surface by 180 degrees is called a solid sphere. (Defined from the perspective of rotation)

(3) Take the straight line where the diameter of the circle is located as the rotation axis, and the rotating body formed by rotating the circular surface by 180 degrees is called a solid sphere. (Defined from the perspective of rotation)

First, that basic thought and method of calculate the volume of a sphere:First, the ball is intercepted by the plane with the center of the ball. The pepper ball is divided into two hemispheres with equal size by the cross section, and the cross section ⊙ is called the bottom surface of the obtained hemisphere.(l) Step 1: SegmentationCut the hemisphere into layers with a set of planes parallel to the bottom surface.(2) Step 2: Find approximate sum.Each layer is a "small disc" with an approximate cylindrical shape. We approximate the volume of the "small disc" with a small cylindrical volume, and their sum is the approximate volume of the hemisphere.(3) Step 3: Transform approximate sum into exact sum.When it increases infinitely, the approximate volume of the hemisphere tends to the exact volume.Second, the mathematical language representation:There is a circle X 2+Y 2 = R 2. Let the circle rotate around the X axis in the xoy coordinate axis to get a sphere.The infinitesimal of pepper ball volume is dv = π [√ (r 2-x 2)] 2dx.∫ dv = ∫ π [√ (r 2-x 2)] 2dx integration interval is [-r,r].Get the result as f