Answer:
1638.89 kg/m³
Explanation:
From the question,
R.D = Upthrust of the rock in liquid/upthrust of the rock in water = Density of liquid/Density of water.
U'/U = D'/D............................ Equation 1
Where U' = Upthrust in liquid = Weight of rock in air- weight of rock in liquid,
U = Upthrust in water = weight of rock in air - weight of rock in water, D' = Density of liquid, D = Density of water.
make D' the subject of the equation
D' = (U'/U)D................... Equation 2
Given: U' = 39.2-21.5 = 17.7 N, U = 39.2-28.4 = 10.8 N
Constant: D = 1000 kg/m³
Substitute these values into equation 2
D' = (17.7/10.8)1000
D' = 1638.89 kg/m³
