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4 years ago

How did Aristotle's inability to detect parallax lead him to propose a geocentric model of the Solar System.

1 answer:

6 0

He reasoned that since parallax could not be observed for celestial objects near the sun, then the earth was stationary. This erroneous assumption was because at the time he had no way of knowing that celestial objects were so far away that their parallax angles were too small to detect.

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The percent by which the fundamental frequency changed if the tension is increased by 30 percent is ? a)-20.04% b)-40.12% c)-30%

nika2105 [10]

Answer:

Percentage increase in the fundamental frequency is

d)-14.02%

Explanation:

As we know that fundamental frequency of the wave in string is given as

$f_o = \frac{1}{2L}\sqrt{\frac{T}{\mu}}$

now it is given that tension is increased by 30%

so here we will have

$T' = T(1 + 0.30)$

$T' = 1.30T$

now new value of fundamental frequency is given as

$f_o' = \frac{1}{2L}\sqrt{\frac{1.30T}{\mu}}$

now we have

$f_o' = \sqrt{1.3}f_o$

so here percentage change in the fundamental frequency is given as

$change = \frac{f_o' - f_o}{f_o} \times 100$

% change = 14.02%

3 0

3 years ago

Ocean waves are hitting a beach with a frequency of 0.100 Hz. Their average wavelength is 15.0 m. What is their average speed?

den301095 [7]

Answer:

Average speed=1.5 m/s

Frequency of pendulum=93.75Hz

Explanation:

We are given

Frequency, $f=0.100Hz$

Average wavelength = $\lambda=15m$

Speed of pendulum, $v=30m/s$

Wavelength, $\lambda'=0.32m$

We have to find the average speed and frequency of pendulum.

We know that

Speed, $v=\lambda f$

Using the formula

Average speed, $v=15\times 0.1=1.5m/s$

Hence, the average speed =1.5m/s

Frequency, $f=\frac{v}{\lambda'}$

Using the formula

$f=\frac{30}{0.32}$

$f=93.75Hz$

Hence, the frequency of a pendulum=93.75Hz

6 0

3 years ago

In a given chemical reaction the energy of the products is less than the energy of the reactants which statement is true for thi

GREYUIT [131]

Group of answer choices.

A. Energy is absorbed in the reaction.

B. Energy is released in the reaction.

C. There is no transfer of energy in the reaction.

D. Energy is lost in the reaction.

Answer:

B. Energy is released in the reaction.

Explanation:

A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.

Basically, there are two (2) main types of chemical reaction and these include;

I. Endothermic reaction: it's a chemical reaction in which heat is absorbed

II. Exothermic reaction: it's a chemical reaction in which heat is liberated into the environment.

In Chemistry, all chemical equation must follow or be in accordance with the Law of Conservation of Mass, which states that mass can neither be created nor destroyed by either a physical transformation or a chemical reaction but transformed from one form to another in an isolated (closed) system.

Generally, energy is released in a chemical reaction when the energy of the products is less than the energy of the reactants and it is referred to as an exothermic reaction.

However, when the energy of the products is greater than the energy of the reactants, energy is absorbed and it is referred to as an endothermic reaction.

5 0

3 years ago

How much will be the net displacement if a car travels 6 km east and then travels 14 km west

ExtremeBDS [4]

8km is the displacement

5 0

3 years ago

Q 24, 25, 26 i dont get them and need answers for it

Alexandra [31]

Answer:

24) W = 75 [J]; 25) W = 1794[J]; 26) n = 8.8 (times) or 9 (times)

Explanation:

24) This problem can be solved by means of the following equation.

$DU = Q-W\\$

where:

DU = internal energy difference [J]

Q = Heat transfer [J]

W = work [J]

Since there are no temperature changes the internal energy change is equal to zero

DU = 0

therefore:

$Q = W\\$

The work is equal to the heat transfered, W = 75 [J].

25) The heat transfer can be calculated by means of the following equation.

$Q = m*c_{p}*DT\\where:\\m = mass = 0.4[kg]\\c_{p} = specific heat = 897[J/kg*K]\\DT= 5 [C]$

Q = 0.4*897*5 = 1794[J]

Work is equal to heat transfer, W = 1794[J]

26) Each time the bag falls the potential energy is transformed into heat energy, which is released into the environment. In this way the potential energy is equal to the developed heat.

$E_{p}=Q\\\\E_{p}=m*g*h$

where:

m = mass = 0.5[kg]

g = gravity = 9.81[m/s^2]

h = 1.5 [m]

$E_{p}=0.5*9.81*1.5\\E_{p}=7.36[J]$

The heat developed can be calculated by means of the following equation.

$Q=m*c_{p}*DT\\Q=0.5*130*1\\Q=65[J]$

The number of times will be calculated as follows

n = 65/7.36

n = 8.8 (times) or 9 (times)

7 0

4 years ago