Question

In the figure is known the density of water type 1000 and the mass of oil type 800. If the beam with side 10 cm and 20% part is in water. mass of beam is?

Answer 1

R = 10 cm = 0.1 m

Ρm = 800 kg / m³
Vt = 20% = ¹ / ₅ portion of volume
M = __?


Volume of logs
V = r³
     = (0.1) ³ = 10³ m³


     F = ρm g Vt
M g = ρm g Vt
    M = ρm Vt
        = 800 · ¹ / ₅ × 10⁻³
        = 0.16 kg 

The mass of the wooden beam is 0.16 kg