Se deja caer una piedra en un pozo y al cabo de 10s se oye el choque contra el fondo si la velocidad de sonido es de 330 m/s. ¿ Cuál es la profundidad del pozo?
Translate : Physically, a stone is dropped into a well and after 10 seconds you can hear the crash against the bottom, if the speed?
Answer : 383 m
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What is true about protein?
A.
Your body needs it to build and repair tissue.
B.
It is best to get it from the food you eat.
C.
Too much can damage your kidneys.
D.
All of the above
Answer:
D
Explanation:
Light traveling through air encounter a second medium which slows the light to 2.7 x 10^8. What is the index of the medium?
Answer:
1.11
Explanation:
The index of the medium can be calculated using below formula
V= c/ n ............eqn(1)
Where V= velocity of the light is reduced to while traveling through the second medium= 2.7 x 10^8 m/s
n= index of the medium
c= speed of light= 3 x 10^8 m/s
Substitute for the values in eqn(1)
2.7 x 10^8 = (3 x 10^8 m/s)/ n
Making " n" subject of the formula, we have
n= (3 x 10^8 )/(2.7 x 10^8)
n= 1.11
Hence, the index of the medium is 1.11
Consider two walls, A and B, with the same surface areas and the same temperature drops across their thicknesses. The ratio of their thermal conductivities is kA/kB=4 and the ratio of the wall thickness is LA/LB=2. The ratio of heat transfer rates through the walls qA/qB is:
(a) 0.5
(b) 1
(c) 2
(d) 4
(e) 8
(f) None of them
Answer:
(c) 2
Explanation:
Heat transfer across the walls due to conduction is given by:
[tex]q = -KA\frac{\Delta T}{L}[/tex]
where,
q = heat transfer rate
K = thermal conductivity
A = Area
ΔT = change in temperature
L = thickness
For wall A:
[tex]q_A = -K_AA\frac{\Delta T}{L_A}[/tex]
For wall B:
[tex]q_B = -K_BA\frac{\Delta T}{L_B}[/tex]
Because the change of temperature and area of walls are the same. Dividing both terms:
[tex]\frac{q_A}{q_B} = \frac{\frac{K_A}{L_A} }{\frac{K_B}{L_B}}\\\\ \frac{q_A}{q_B} =\frac{\frac{K_A}{K_B} }{\frac{L_A}{L_B}}[/tex]
using values given in the question:
[tex]\frac{q_A}{q_B} = \frac{4}{2}\\\\\frac{q_A}{q_B} = 2[/tex]
Therefore, the correct answer is:
(c) 2
7
Select the correct location on the image.
Objects A and B are brought close to each other. Object A will soon become positively charged. Identify the charge that must transfer for this
situation to occur.
+
A
B
Answer:
Explanation:
For A to become positively charged, a + charge must transfer from B to A.
The charge that must transfer for object A to become positively charged is the negative charge in object A.
What is charging by conduction?Charging by conduction occurs when a charged object causes the flow of electron when it comes in contact with an uncharged object.
An object can either be negatively or positively charged. An object is said to be positively charged when it contains more protons than electron.
Therefore, for object A to be positively charged, the charge that must transfer for object A to become positively charged is the negative charge.
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You have an electric field with an intensity of 18 N/C at a
distance of 6.0 m. What is the voltage?
Answer:
108 v
Explanation:
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In a real pully system the work supplied must be _____ the work accomplished
What are some examples of gravitational forces that keep an object in orbit? Pls give at least 2-3 example if you can.
Answer:
Without any external forces a moving object will continue to move in a straight line. The gravitational force between the two objects will provide the centripetal force to keep the objects moving around one another.
1. satellite in orbit around the earth (motion of earth is negligible)
2. moon in orbit around the earth (center of motion several thousand miles
from center of earth)
3. earth in orbit around sun (center of rotation close to center of sun)
4. binary stars (if masses of stars are equal center of rotation is in middle)
12. A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of
60 kg, how long did it take him to reach that speed?
We have that the Time it took him to reach that speed is
t=1.2sec
From the question we are told
A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of 60 kg, how long did it take him to reach that speed?
Generally the equation for the is mathematically given as
[tex]P=W/t[/tex]
Therefore
[tex]W=Pt\\\\W=250*t[/tex]
Where
[tex]W=f*d\\\\5*60=250*t\\\\t=\frac{5*60}{250}]\\\\t=1.2sec[/tex]
Therefore
Time it took him to reach that speed is
t=1.2sec
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To pull apart two pieces of wood, you can apply a force of 50 N to a lever. The lever applies a force of 640 N. What is the mechanical advantage of
the lever?
A.13
B.17
C.0.08
D.32,000
what’s answer? pls help will mark brainliest
PLS HELP, WILL GIVE BRAINLIEST
Answer:
B. x = 50, Y = 100 ,Z= 150
sorry if it's wrong
Question 3 of 25
Matter can undergo chemical reactions and nuclear reactions. Which feature
of the components only stays the same in chemical reactions?
A. Chemical bonds between atoms
B. Number of compounds
O
C. Types of compounds
O D. Numbers of atoms
Answer:
D. Numbers of atoms
Explanation:
The feature of the components of matter that only stays the same in chemical reactions is: D. numbers of atoms.
What is the law of conservation of matter?The law of conservation of matter (LOCOM) states that mass can neither be created nor destroyed in any chemical reaction.
This ultimately implies that, a balanced chemical equation would always require the same number of atoms on both the reactant side and product side of a chemical reaction.
In conclusion, we can deduce that the feature of the components of matter that only stays the same in chemical reactions is: D. numbers of atoms.
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Help pls and. No links pls
Answer:
the answer to this question will be False
Answer:
false.......,.....,...........
Help me please
Which line shows the LOWEST frequency?
PLEASE HELP WILL MARK BRAINLIEST
Answer:
Protium
Explanation: Protium is an isotope of hydrogen that is composed of one proton and one electron. It is the most abundant form of hydrogen.
Answer:
To be honest. I think all three of them are hydrogen i know Deuterium and Tritium are so I decided to research about protium and it said its also hydrogen.
Explanation:
Protium Deuterium and Tritium are all isotopes of hydrogen
A laserbeam takes 24ms to travel from a rocket to a reflective surface of a planet and back to the rocket. How far, in miles, is the rocket from this planet’s surface?
A)2200 miles
B)3600 miles
C)2400 miles
please show work, thank you!
Answer:B
Explanation:
What causes the inner core to be solid?
A) Intense heat.
B) Intense pressure.
C) Because it is made of iron.
D) Because of it’s density.
Caso #1 Leo Messi está jugando la final de la Champion league 2019-2020 y va a cobrar un tiro libre importante, necesita aplicar un análisis para poder alcanzar su objetivo que es acertar el gol. Responder
Answer:
Tiene que patear el balón cerca del nivel del suelo para conseguir el gol.
Explicación:
Leo Messi necesita patear el balón no en el aire, en el nivel del suelo para poder meter el gol para el equipo. Delante del fútbol hay muchos jugadores del equipo contrario dispuestos a detener el tiro libre de Leo Messi. Cuando Leo Messi patea el balón en el aire, los jugadores también saltan en el aire para detener el tiro libre que atraviesa la cabeza y para conseguir el gol Leo Messi tiene que evitar patear el balón en el aire y patear el balón cerca del nivel del suelo. que puede atravesar a los jugadores oponentes cuando lo saltan para detener el balón a través de sus cabezas para que el balón pase por debajo de sus pies y llegue a la portería.
If an object has a mass of 15 kg and has a weight of 30 N, on some remote
planet, what would be the acceleration due to gravity on that planet?
On a distance-time graph, time is shown on the y-axis.
A) True
B) False
Answer:
false : In distance time graph,time is shown on the x -axis
La temperatura de cambio de estado, ¿Puede ser igual para todos los materiales? Justifica comparando dos materiales
Answer:
No.
Explanation:
Para darnos cuenta de esto tenemos que pensar en lo siguiente:
Pensemos en un vaso de vidrio, lleno de agua hasta la mitad, la otra mitad puede ser manteca derretida
Si metemos el vaso en la heladera durante un par de horas, (sabemos que la manteca en la heladera se mantiene sólida) veremos que la manteca se solidificó en la parte de arriba, mientras que el agua sigue líquida.
Entonces encontramos dos compuestos con distintas temperaturas para cambio de fase, pero materiales es más específico, y puede referirse a materiales puros.
Entonces vamos a dos metales:
Primero tenemos una pieza de hierro y una de mercurio en el congelador (supongamos que ambas están a 0°C).
Ahora los sacamos del congelador y los dejamos llegar a temperatura ambiente.
Como bien sabemos, el mercurio es líquido a temperatura ambiente, entonces el mercurio va a sufrir un cambio de fase
Ahora pensemos en el hierro; claramente va a seguir siendo sólido a temperatura ambiente, entonces podemos ver dos materiales cuyo cambio de fase de sólido a líquido ocurre en distintas temperaturas, por lo que podemos concluir que no, la temperatura de cambio de estado no puede ser igual para todos los materiales, y esto se debe a que la estructura atómica de todos los materiales es diferente.
Why does it take more time for a larger sample of water to freeze?
Answer:The greater the amount of water that there is it will take longer for the water to freeze because more heat has to be dissipated into the environment
Explanation:
Answer:
The greater the mass of water, the more heat has to be dissipated into the environment and the longer it will take to freeze. The greater the surface area of the water, the faster the water will lose its heat and freeze.
an athlete in a hammer-throw event swings a 7.0-kilogram hammer in a horizontal circle at a constant speed of 12 meters per second. The radius of the hammer's path is 2.0 meters.
Answer:
ac = 72 m/s²
Fc = 504 N
Explanation:
We can find the centripetal acceleration of the hammer by using the following formula:
[tex]a_c = \frac{v^2}{r}[/tex]
where,
ac = centripetal acceleration = ?
v = constant speed = 12 m/s
r = radius = 2 m
Therefore,
[tex]a_c = \frac{(12\ m/s)^2}{2\ m}[/tex]
ac = 72 m/s²
Now, the centripetal force applied by the athlete on the hammer will be:
[tex]F_c = ma_c\\F_c = (7\ kg)(72\ m/s^2)[/tex]
Fc = 504 N
write functions of simple machine
Answer:
The basic purpose for which most simple machines are designed is to reduce the effort (force) required to perform a simple task. To achieve this, the force applied must act over a longer distance or period of time resulting in the same amount of work being performed by a smaller force.
Answer:
to make work easier by reducing the effort to be used
Explanation:
2. What is the total voltage drop across
the first and second resistor?
8v
10v
0 12v
Answer: 8v
Explanation:
The total voltage drop across the first and second resistor is 8 V, hence option A is correct.
What is Voltage?Voltage is the fluctuation in electric potential between the two places. It is sometimes produced by electric pressure, electric tension, or voltage source. The work required to move a test charge between two places in a static electric field corresponds to this. The derived measure for voltage in the International System of Units is called a volt. Work per unit energy is expressed in SI units as joules per coulomb, with 1 volt equaling 1 joule per 1 coulomb.
To detect the voltages between two locations in a circuit, use a voltmeter. A common reference point, like the system's foundation, is frequently utilized as one of the points.
A voltage can indicate either a supply of energy or its loss, dissipation, or storage.
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Use the kinetic theory of matter to explain thermal expansion in liquids (2marks)
Answer:
Explanation:
When a substance is heated the average kinetic energy of molecules increases and they start moving with an increased speed.As a result between mean separation between the molecules also increases
What is the relationship between the density of a substance and the speed of sound through that substance?
Answer:The greater the density of a medium, the slower the speed of sound. This observation is analogous to the fact that the frequency of a simple harmonic motion is inversely proportional to m, the mass of the oscillating object. The speed of sound in air is low, because air is easily compressible.
Explanation:
3/8 of light initial intensity is absorbed in the breaker with length of 2cm filled with 9% solution. Find the length of the beaker should be used to get transmittance 1/3 for the same solution
Answer:
Assume I1 = Io * T1 transmission proportional to thickness
I2 = Io * T2 I is intensity of light absorbed (3/8 absorbed)
I1 / I2 = T1 / T2
T2 = T1 * (I2 / I1) = 2 * (2/3 / 3/8) = 2 * 16/9 = 32/9 thickness for 2/3 absorbed
The length of the beaker when the transmittance is changed to one-third is 13.78 cm.
The given parameters;
length of the beaker when 3/8 of the light intensity is absorbed = 2 cm = 0.02 mTo find:
the length of the beaker when there is 1/3 transmittanceThe length of the beaker is calculated by applying Beer-Lambert law;
[tex]\frac{I}{I_o} = e^{-cl}[/tex]
[tex]\frac{I_1}{I_0} = e^{-cl_1} = \frac{3}{8} \ ----(1)\\\\\frac{I_2}{I_0} = e^{-cl_2}= \frac{1}{3} \ ---- (2)[/tex]
divide equation (1) by equation (2);
[tex]\frac{e^{-cl_1}}{e^{-cl_2}} = \frac{3}{8} \times \frac{3}{1} \\\\ (c \ is \ constant \ for \ both) \\\\e^{-l_1 + l_2} = \frac{9}{8} \\\\l_2 - l_1 = ln(\frac{9}{8} )\\\\l_2 - 0.02 = 0.1178\\\\l_2 = 0.1178 + 0.02\\\\l_2 = 0.1378 \ m\\\\l_2 = 13.78 \ cm[/tex]
Thus, the length of the beaker when the transmittance is changed to one-third is 13.78 cm.
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