1. An object in the shape of a semicircle of radius 4 cm has varying density. The density changes linearly depending on the h value as shown in the picture, from
1 g/cm at the bottom to 3 g/cm at the top. What is the total mass of the object?
Explain your work.

58 i think in 5 hours he makes $58

Planet earth has a mass of 5.9726x10²⁴ kg.then: 5.9726x10²⁴ kg=100% of the total earth mass.if the water´s mass=5x10-4 % of the total mass, we can solve this problem by the rule of three.5.9726x10²⁴ %*10⁻⁴ %x=(5.9726x10²³ kg)(5*10⁻⁴  %) / 100 %=2.9863x10¹⁹ kganswer:   the mass of the planet´s water would be   2.9863 x 10¹⁹ kg.

This seems very interesting. i think i can !