Answer:
A. Its unique strength allows predetermined engineering stresses to be placed in members to counteract stresses that occur when the unit is subjected to service loads
Explanation:
Prestressed concrete is a structural material that allows for predetermined, engineering stresses to be placed in members to counteract the stresses that occur when they are subject to loading.
It combines the high strength compressive properties of concrete with the high tensile strength of steel.
‘Building Construction Handbook’ (6th ed.), CHUDLEY, R., GREENO, R., Butterworth-Heinemann (2007)
Then the correct answer is:
A. Its unique strength allows predetermined engineering stresses to be placed in members to counteract stresses that occur when the unit is subjected to service loads
Answer:
18%
Explanation:
There are two equal and opposite forces on a floating object: weight and buoyancy.
W = B
The weight of an object is its mass times gravity: W = mg
Buoyancy is the weight of the displaced fluid: W = mf g
Plugging in:
mg = mf g
m = mf
Mass is density times volume:
ρV = ρf Vf
Solving for the ratio of Vf / V:
Vf / V = ρ / ρf
Given that ρ = 0.82 g/mL and ρf = 1.00 g/mL:
Vf / V = 0.82
That means 82% of the object's volume (and therefore, 82% of its mass, assuming uniform density) is submerged. Which means that 18% is above the water line.
Answer:
The disorder in the universe is increasing with time.
Explanation:
The second law of thermodynamics states that the amount of entropy in the universe increases over time. Entropy expresses the number of different configurations that a system defined by macroscopic variables could assume. Therefore, is can be interpreted as a measure of the disorder, or randomness of a system.
The strength of the gravitational force between two objects depend on two factors, mass and distance.
