Final answer:
The weight of the combined system of the 3-kg plastic tank filled with liquid water is 1989.4 N, calculated based on the density of water and the volume of the tank.
Step-by-step explanation:
The combined weight of the plastic tank and the water can be determined by calculating the mass of the water and adding it to the mass of the tank. To calculate the mass of the water, we use the following relation where mass (m) is the product of density (ρ) and volume (V): m = ρ × V.
Given the volume of the tank is 0.2 m³ and the density of water is 1000 kg/m³, the mass of water can be calculated as:
m = 1000 kg/m³ × 0.2 m³ = 200 kg.
The combined mass of the tank and water is:
3 kg (tank mass) + 200 kg (water mass) = 203 kg.
To find the weight, we multiply the combined mass by the acceleration due to gravity (g ≈ 9.8 m/s²):
Weight = 203 kg × 9.8 m/s² = 1989.4 N (Newtons).