Answer:
2400 kilogram per cubic meter
Explanation:
the density of concrete is a measure of its unit weight.
concrete is a mixture of cement, fine and coarse aggregates, water and sometimes some supplementary materials like fly ash, and various admixtures.
Answer is 3. Volume= mass divided by density
Oh your from the other question you made I just saw it LOL.
But heres the answer click the 3 dots on the question you made or you can ask a Moderator or Administrator to remove your question with a reason.
I'll say that's mechanical weathering
Answer:
y = 80.2 mille
Explanation:
The minimum size of an object that can be seen is determined by the diffraction phenomenon, if we use the Rayleigh criterion that establishes that two objects can be distinguished without the maximum diffraction of a body coincides with the minimum of the other body, therefore so much for the pupil of the eye that it is a circular opening
θ = 1.22 λ/ d
in a normal eye the diameter of the pupils of d = 2 mm = 0.002 m, suppose the wavelength of maximum sensitivity of the eye λ = 550 nm = 550 10⁻⁹ m
θ = 1.22 550 10⁻⁹ / 0.002
θ = 3.355 10⁻⁴ rad
Let's use trigonometry to find the distance supported by this angle, the distance from the moon to the Earth is L = 238900 mille = 2.38900 10⁵ mi
tan θ = y / L
y = L tan θ
y = 2,389 10⁵ tan 3,355 10⁻⁴
y = 8.02 10¹ mi
y = 80.2 mille
This is the smallest size of an object seen directly by the eye
