Step 1: Convert relative density to density: ρ = 0.8 × 1000 kg/m³ = 800 kg/m³
Step 2: Use the pressure formula P = ρgh. Rearrange to find depth h = P / (ρg)
Step 3: h = 120,000 N/m² / (800 kg/m³ × 9.8 m/s²) = 15.31 m. (Note: The question's unit for pressure is likely a typo and should be kN/m²)

For steady-state fluid flow, common assumptions include the fluid being non-viscous (ideal fluid), incompressible, and having laminar flow. Turbulent motion, characterized by chaotic and unpredictable changes in flow, contradicts the assumption of steady-state flow.

Fluids are substances that continuously deform (flow) under an applied shear stress. This definition encompasses both liquids and gases, as they both lack a fixed shape and will alter their form in response to an external force.

Step 1: Convert dimensions to meters: 40cm = 0.4m, 80cm = 0.8m
Step 2: Calculate area: Area = 0.4m × 0.8m = 0.32 m²
Step 3: Calculate force: Force = Pressure × Area = 1.0 × 10⁵ Pa × 0.32 m² = 3.2 × 10⁴ N

Step 1: Calculate force (weight): F = mg = 8 kg × 9.8 m/s² = 78.4 N
Step 2: Calculate radius: r = diameter / 2 = 0.13 cm / 2 = 0.065 cm = 0.00065 m
Step 3: Calculate cross-sectional area: A = πr² = π × (0.00065 m)² = 1.327 × 10⁻⁶ m²
Step 4: Calculate stress: Stress = F/A = 78.4 N / 1.327 × 10⁻⁶ m² = 5.91 × 10⁷ Pa

Step 1: Calculate force (weight): F = mg = 4500 kg × 9.8 m/s² = 44100 N
Step 2: Convert base dimensions to meters: 35 cm = 0.35 m, 40 cm = 0.40 m
Step 3: Calculate area: A = 0.35 m × 0.40 m = 0.14 m²
Step 4: Calculate pressure: P = F/A = 44100 N / 0.14 m² = 315000 Pa = 3.15 × 10⁵ Pa

The apparent weight of a body immersed in a fluid is its actual (real) weight minus the buoyant force exerted by the fluid. This is a direct application of Archimedes' principle, where the buoyant force acts upwards, reducing the effective downward force.

Step 1: Calculate strain: Strain = ΔL / L = 0.035 cm / 75.0 cm = 0.0004666
Step 2: Calculate Young's Modulus: Y = Stress / Strain = (5.91 × 10⁷ Pa) / 0.0004666 = 1.266 × 10¹¹ Pa = 127 GPa

Intermolecular forces arise from electromagnetic interactions between molecules. These forces, such as van der Waals forces and hydrogen bonds, are fundamentally electrostatic in nature, involving the attraction and repulsion of charges and dipoles within and between molecules.

Ionization involves removing electrons from atoms or molecules. Heating provides thermal energy, collisions with fast particles transfer kinetic energy, and high-energy electromagnetic radiation (like UV or X-rays) provides photon energy, all of which can cause ionization. Chemical interaction between molecules typically involves sharing or transferring electrons, but doesn't directly increase ionization in the same way as the other methods.

Step 1: Convert volume to m³: V = 250 cm³ = 250 × 10⁻⁶ m³
Step 2: Convert diameter to radius in meters: r = 7.0 mm / 2 = 3.5 × 10⁻³ m
Step 3: Calculate flow rate Q = V/t = 250 × 10⁻⁶ m³ / 4 s = 6.25 × 10⁻⁵ m³/s
Step 4: Calculate cross-sectional area A = πr² = π × (3.5 × 10⁻³ m)² = 3.848 × 10⁻⁵ m²
Step 5: Calculate average speed v = Q/A = 6.25 × 10⁻⁵ m³/s / 3.848 × 10⁻⁵ m² = 1.62 m/s