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3 years ago

Which best explains why scientific theories grow stronger over time?

1 answer:

3 0

If a theory is studied in let's say the 17th century, the theory has had many years to be studied and explained by many different people many different ways.

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What are dimensionless quantities??

bearhunter [10]

Answer:

Characteristic numbers are dimensionless numbers used in fluid dynamics to describe a character of the flow. To compare a real situation with a small-scale model it is necessary to keep the important characteristic numbers the same. Names of these numbers were standardized in ISO 31, part 12.

Explanation:

7 0

2 years ago

A car slams on its breaks,producing friction between the tires and the road.Into which type of energy is the mechanical energy o

Step2247 [10]

The answer is Heat Energy

4 0

3 years ago

Read 2 more answers

A 19.12 g mixture of Ca(NO3)2 and KCl is dissolved in 149 g of water. The freezing point of the solution was measured as −5.77 ∘

hichkok12 [17]

Answer:

The mass percentage of calcium nitrate is 31.23%.

Explanation:

Let the the mass of calcium nitrate be x and mass of potassium chloride be y.

Total mass of mixture = 19.12 g

x + y = 19.12 g..(1)

Mass of solvent = 149 g = 0.149 kg

Freezing point of the solution, $T_f$ = -5.77 °C

Molal freezing constant of water = 1.86 °C/m =1.86 °C/(mol/kg)

The van't Hoff factor contribution by calcium nitrate is 3 and by potassium chloride is 2.So:

i = 3

i' = 2

Freezing point of water = T = 0°C

$\Delta T_f=T-T_f=0^oC-(-5.77^oC)=5.77^oC$

$\Delta T_f=i\times K_f\times m$

$Molality=m(mol/kg)=\frac{\text{Moles of solute}}{\text{mass of solvent in kg}}$

$5.77^oC=1.86 ^oC/(mol/kg)\times (\frac{ i\times x}{164 g/mol\times 0.149 kg}+\frac{i'\times y}{74.5 g/mol0.149 kg})$

On solving we get:

$\frac{3x}{164 g/mol}+\frac{2x}{74.5 g/mol}=0.4622 mol$ ....(2)

Solving equation (1)(2) for x and y:

x =5.973 g

y = 13.147 g

Mass percent of $Ca(NO_3)_2$ in the mixture:

$\frac{x}{19.21 g}\times 100=\frac{5.973 g}{19.12 g}=31.23\%$

The mass percentage of calcium nitrate is 31.23%.

5 0

3 years ago

Select the correct answer

Rasek [7]

Answer:

I would say the net force acting on the car is in the opposite direction of the car's motion is correct

5 0

2 years ago

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Situations in which it is difficult for an individual to decide, either because the right course of action is not clear or becau

galina1969 [7]

Answer:

ethical dilemmas or ethical paradox

Explanation:

Ethical dilemmas or ethical paradox or moral dilemma is a situation in which a difficult choice has to be made between two or more courses of action, either because the right course of action is not clear or because the right course of action carries some negative consequences. one example is selling a bad product so as not to loose your cost.

6 0

3 years ago