All categories

3 years ago

Ptolemys date of theory! PLEASE HELP

1 answer:

8 0

Mathematical model of the universe formulated by the Alexandrian astronomer and mathematician Ptolemy about ad 150 and recorded by him in his Almagest and Planetary Hypotheses. The Ptolemaic system is a geocentric cosmology; that is, it starts by assuming that the Earth is stationary and at the centre of the universe. The “natural” expectation for ancient societies was that the heavenly bodies (Sun, Moon, planets, and stars) must travel in uniform motion along the most “perfect” path possible, a circle. However, the paths of the Sun, Moon, and planets as observed from the Earth are not circular. Ptolemy’s model explained this “imperfection” by postulating that the apparently irregular movements were a combination of several regular circular motions seen in perspective from a stationary Earth. The principles of this model were known to earlier Greek scientists, including the mathematician Hipparchus (c. 150 bc), but they culminated in an accurate predictive model with Ptolemy. The resulting Ptolemaic system persisted, with minor adjustments, until the Earth was displaced from the centre of the universe in the 16th and 17th centuries by the Copernican system and by Kepler’s laws of planetary motion.

You might be interested in

A NaOH solution is standardized using the monoprotic primary standard potassium hydrogen phthalate, KHP (204.22 g/mol.) If 0.698

kakasveta [241]

Answer:

0.07789 M is the sodium hydroxide concentration.

Explanation:

Mass of potassium hydrogen phthalate = 0.6986 g

Molar mass of potassium hydrogen phthalate = 204.22 g/mol

Moles of potassium hydrogen phthalate = $\frac{0.6986 g}{204.22 g/mol}=0.003421 mol$

$NaOH+KHP\rightarrow NaKP+H_2O$

According to reaction , 1 mole og KHp reactswith 1 mole of NaOH , then 0.003421 moles of KHp will react with :

$\frac{1}{1}\times 0.003421 mol=0.003421 mol$

Moles of NaOH = 0.003421 mole

Volume of NaOH solution = 43.92 ml = 0.04392 L ( 1 mL = 0.001L)

$Concentration=\frac{Moles}{Volume(L)}$

Concentration of NaOH :

$\frac{0.003421 mol}{0.04392 L}=0.07789 M$

0.07789 M is the sodium hydroxide concentration.

5 0

3 years ago

A horse pulls on a cart with a force of 1800 newtons. The cart accelerates at the rate of 4.39 m/s2. According to Newton's law o

AlladinOne [14]

Answer:

Answer = 410.02277904328

Explanation:

1,800 N * $4.39m/s^2$ = 410.02277904328 m

hope this helps.

7 0

3 years ago

The bonds S-S, O-H and Ca-Cl are, respectively, a) nonpolar covalent, polar covalent, ionic polar covalent, b)nonpolar covalent,

Brums [2.3K]

Answer:

nonpolar covalent, polar covalent, ionic

Explanation:

From the question ,

S - S Bond -

Both the atom are same , hence , making a non polar bond , because of no difference between the electronegativity of the atom ,

Hence , the S-S Bond is non polar covalent bond .

O-H bond -

The Oxygen atom is more electronegative than the hydrogen atom , so the bond is polar in nature .

And as the bond is formed by sharing ,

Therefore ,

O-H bond is polar covalent bond .

Ca-Cl bond -

Calcium is a metal , whereas , Chlorine is a non - metal , the bond is ionic in nature ,

Hence , Ca-Cl bond is ionic in nature .

7 0

3 years ago

What are two ways in which you can increase the potential energy of a marble on ramp

zlopas [31]

Answer:

You can make the ramp really steep and hold the marble at the top of it

Explanation:

6 0

3 years ago

Gold has an atomic weight of 196.97 g/mol, and a density of 19.3 g/cm3. Approximately how many atoms are in a spherical gold nan

ale4655 [162]

Answer: The number of atoms in spherical gold nano particle are $26.918\times 10^4$

Explanation:

To calculate the volume of sphere, we use the equation:

$V=\frac{4}{3}\pi r^3$

where,

r = radius of the sphere = $10nm=10^{-6}cm$ (Conversion factor: $1nm=10^{-7}cm$ )

Putting values in above equation, we get:

$V=\frac{4}{3}\times 3.14\times (10^{-6})^3\\\\V=4.19\times 10^{-18}cm^3$

To calculate mass of of the substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Volume of gold = $4.19\times 10^{-18}cm^3$

Density of gold = $19.3g/cm^3$

Putting values in above equation, we get:

$19.3g/cm^3=\frac{\text{Mass of gold}}{4.19\times 10^{-18}}\\\\\text{Mass of gold}=8.0867\times 10^{-17}g$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Mass of gold = $8.8067\times 10^{-17}g$

Molar mass of gold = 196.97 g/mol

Putting values in above equation, we get:

$\text{Moles of gold}=\frac{8.8067\times 10^{-17}g}{196.97g/mol}=4.47\times 10^{-9}moles$

According to mole concept:

1 mole of an element contains $6.022\time 10^{23}$ number of atom

So, $4.47\times 10^{-19}$ moles of gold will contain = $4.47\times 10^{-19}\times 6.022\times 10^{23}=26.918\times 10^4$ number of atoms.

Hence, the number of atoms in spherical gold nano particle are $26.918\times 10^4$

8 0

3 years ago