Answer:
Valence electrons are outer shell electrons with an atom and can participate in the formation of chemical bonds. In single covalent bonds, typically both atoms in the bond contribute one valence electron in order to form a shared pair. The ground state of an atom is the lowest energy state of the atom.
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The Moon itself does not produce light. It appears to be lit because it is _____________ light from the Sun. *
A)absorbing
B)Reflecting
C)capturing
D)stealing
Answer:
it's b the moon reflect light from the sun
¿Cuáles de las siguientes cualidades permiten identificar un cuerpo como planeta? I) Debe ser aproximadamente esférico. II) Debe girar en torno a una estrella. III) Su velocidad debe ser constante.
Answer:
The correct answer is ii) It must revolve around a star
Explanation:
For a celestial body to be called a planet, it must meet at least three characteristics
* rotate around a star
* its mass must be sufficient to maintain hydrostatic equilibrium
* have control over its orbital that is to say to prevent that other body is in its same orbital
if we check the different proportions
i) False. Most of the planets are spheres deformed by their rotation on themselves and around the star
ii) True. It is in accordance with the minimum characteristics of the plants
iii) False .. the orbit of the planet can be elliptical and the speed changes at each point for this at a different distance from the star that is in a focus of the ellipse.
The correct answer is ii) It must revolve around a star
A skier traveling downhill has this type of energy
Answer:
potential energy
Explanation:
are positively charged ions form when atoms lose electrons
Answer: Atoms that lose electrons acquire a positive charge as a result because they are left with fewer negatively charged electrons to balance the positive charges of the protons in the nucleus. Positively charged ions are called cations. Most metals become cations when they make ionic compounds.
Explanation: hope this helps
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Explain to me in YOUR own words, how convection currents create a cycle? In other words, tell me how heat and cooling create a cycle.
Answer:
because it get the energy from the heat and the cold mixed together
Explanation:
The plates on a vacuum capacitor have a radius of 3.0 mm and are separated by a distance of 1.5 mm. What is the capacitance of this capacitor?
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Answer:
C. The lever applies three times more force than you hand can apply.
Explanation:
Since it's advantage is 3, that means you'll have to multiply the input of it by 3, making this apply 3x more force than your hand.
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A group of students are doing a reading activity in their classroom. They suddenly hear the noise of a truck in the parking lot of their school. They can hear it but cannot see it. Which of the following explains why they can hear the truck, but cannot see it?
Answer:
The answer is the sound waves can travel through some material (not all) and visible light cannot.
Explanation:
I did this question on study island so I know the answer.
Answer:
the answer is: sound can be transmitted through the walls, but visible light cannot.
Explanation:
Which of the following occurs when the fight-or-flight response is triggered?
Answer:
A or BExplanation:
The autonomic nervous system has two components, the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system functions like a gas pedal in a car. It triggers the fight-or-flight response, providing the body with a burst of energy so that it can respond to perceived dangers.
At the beginning of a roller coaster ride, the roller coaster car has an initial energy
mostly in the form of PE. Which statement explains why the fastest speeds of the car
will be at the lowest points in the ride?
a. At the bottom of the slope kinetic energy is at its maximum value and potential
energy is at its minimum value.
b. At the bottom of the slope potential energy is at its maximum value and kinetic
energy is at its minimum value.
c. At the bottom of the slope both kinetic and potential energy reach their maximum
values
d. At the bottom of the slope both kinetic and potential energy reach their minimum
values.
Explanation:
The potential energy of the roller coaster is due to its position. It can be calculated as :
P = mgh
Where
m is mass, g is acceleration due to gravity and h is height.
The kinetic energy of an object is given by :
[tex]K=\dfrac{1}{2}mv^2[/tex]
Where
v is the speed of the object
At lowest point, the potential energy of the roller coaster is converted to the kinetic energy. So, At the bottom of the slope kinetic energy is at its maximum value and potential energy is at its minimum value. That's why the speed of the cars is at the lowest points in the ride.
We have that for the Question "Which statement explains why the fastest speeds of the car will be at the lowest points in the ride?"
Option A (At the bottom of the slope kinetic energy is at its maximum value and potential energy is at its minimum value) best explains itoption a explains why the fastest speeds of the car will be at the lowest points in the ride because potential energy decreases with decrease in height. Here the decreased potential energy is converted to the kinetic energy.
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Please help me with 17 and 18!!!!!! (It's related to 16) It's due today!!!!! NO LINK PLEASE!!!!!!!!
Answer:17: A wave can be defined as follows: It is important to realize that a wave is quite a different object than a particle. A baseball thrown though a window transfers energy from one point to another, but this involves the movement of a material object between two points.
Explanation:
18: In this way, we classify waves into electromagnetic and mechanical waves. The main difference between mechanical and electromagnetic waves is that electromagnetic waves do not require a medium to propagate whereas mechanical waves require a medium in order to propagate.
If the elevation of the head of a stream is at 900 feet, and the elevation of the mouth of the stream is 500 feet, and the distance between the two points is 20 miles, and the meandering stream flows 25 miles between those points, what is the gradient of the stream?
Answer:
80 feet per mile
Explanation:
Given that a the elevation of the head of a stream is at 900 feet, and the elevation of the mouth of the stream is 500 feet, and the distance between the two points is 20 miles, and the meandering stream flows 25 miles between those points, what is the gradient of the stream?
The gradient will be calculated by using the formula
M = change in feet ÷ change in miles
Where
M = gradient of the stream.
Change in feet = 900 - 500 = 400 feet
Change in miles = 25 - 20 = 5 miles
M = 400 / 5
M = 80
Therefore, the gradient of the stream is 80 ft per mile
What is the maximum flow rate of water in a smooth pipe 8.0 cm diameter if the flow is to be laminar
Answer:
0.05 m/s
Explanation:
We start by finding the average velocity of water in the pipe. This is done by saying
R(e) = ρv(avg)d/μ
Where,
R(e) = Reynolds number, and that's 2000
ρ = Density of water, 1000 kg/m³
μ = Viscosity of water, 10^-3
d = diameter of pipe
v(avg) = average velocity
Since we're interested in average velocity, we make v(avg) the subject of formula. So that
V(avg) = R(e).μ/ρ.d
V(avg) = 2000 * 10^-3 / 1000 * 0.08
V(avg) = 2 / 80
V(avg) = 0.025 m/s
The maximum flow rate of water in the pipe usually is twice the average velocity, and as such
V(max) = 2 * V(avg)
V(max) = 2 * 0.025
V(max) = 0.05 m/s
The orbital radius of the Earth (the average Earth-Sun distance) is 1.496 × 1011 m. Mercury’s orbital radius is 5.79 × 1010 m and Pluto’s is 5.91 × 1012 m. Calculate the time required for light to travel from the Sun to each of the three celestial bodies
Answer:
Earth: [tex]t = 498.667\,s[/tex], Mercury: [tex]t = 193\,s[/tex], Pluto: [tex]t = 19700\,s[/tex]
Explanation:
The light travels at a constant speed of approximately [tex]3\times 10^{8}[/tex] meters per second. The time ([tex]t[/tex]), in seconds, required for light to travel a given distance is:
[tex]t = \frac{x}{v_{l}}[/tex] (1)
Where:
[tex]x[/tex] - Travelled distance, in meters.
[tex]v_{l}[/tex] - Speed of light, in meters per second.
Now, we calculate the time for light to travel to each planet:
Earth ([tex]v_{l} = 3\times 10^{8}\,\frac{m}{s}[/tex], [tex]x = 1.496\times 10^{11}\,m[/tex])
[tex]t = \frac{x}{v_{l}}[/tex]
[tex]t = 498.667\,s[/tex]
Mercury ([tex]v_{l} = 3\times 10^{8}\,\frac{m}{s}[/tex], [tex]x = 5.79\times 10^{10}\,m[/tex])
[tex]t = \frac{x}{v_{l}}[/tex]
[tex]t = 193\,s[/tex]
Pluto ([tex]v_{l} = 3\times 10^{8}\,\frac{m}{s}[/tex], [tex]x = 5.91\times 10^{12}\,m[/tex])
[tex]t = \frac{x}{v_{l}}[/tex]
[tex]t = 19700\,s[/tex]
1.45 L of 16°C water is placed in a refrigerator. The refrigerator's motor must supply an extra 10.7 W power to chill the water to 6°C in 0.7 hr. What is the refrigerator's coefficient of performance?
Answer:
The coefficient of performance of the refrigerator is 2.251.
Explanation:
In this case, the coefficient of performance of the refrigerator ([tex]COP[/tex]), no unit, is equal to the ratio of the heat rate received from the water to the power needed to work, that is:
[tex]COP = \frac{\dot Q_{L}}{\dot W}[/tex] (1)
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex] (2)
Where:
[tex]\dot Q_{L}[/tex] - Heat rate received from the water, in watts.
[tex]\dot W[/tex] - Power, in watts.
[tex]\rho[/tex] - Density of water, in kilograms per cubic meter.
[tex]V[/tex] - Volume of water, in cubic meters.
[tex]c_{w}[/tex] - Specific heat of water, in joules per kilogram-degree Celsius.
[tex]\Delta T[/tex] - Temperature change, in degrees Celsius.
[tex]\Delta t[/tex] - Cooling time, in seconds.
If we know that [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]V = 1.45\times 10^{-3}\,m^{3}[/tex], [tex]c_{w} = 4187\,\frac{J}{kg\cdot ^{ \circ}C}[/tex], [tex]\Delta T = 10\,^{\circ}C[/tex], [tex]\dot W = 10.7\,W[/tex] and [tex]\Delta t = 2520\,s[/tex], then the coefficient of refrigeration of the refrigerator is:
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex]
[tex]COP = 2.251[/tex]
The coefficient of performance of the refrigerator is 2.251.
A magnifying glass has a converging lens of focal length of 13.8 cm. At what distance from a nickel should you hold this lens to get an Image with a magnification of +2.37?
cm
Answer:
19.6 cm.
Explanation:
From the question given above, the following data were obtained:
Focal length (f) = 13.8 cm
Magnification (M) = +2.37
Object distance (u) =.?
Next, we shall determine the image distance. This can be obtained as follow:
Magnification (M) = +2.37
Object distance (u) = u
Image distance (v) =?
M = v / u
2.37 = v / u
Cross multiply
v = 2.37 × u
v = 2.37u
Finally, we shall determine the object distance. This can be obtained as follow:
Focal length (f) = 13.8 cm
Image distance (v) = 2.37u
Object distance (u) =.?
1/v + 1/u = 1/f
vu / v + u = f
2.37u × u / 2.37u + u = 13.8
2.37u² / 3.37u = 13.8
Cross multiply
2.37u² = 3.37u × 13.8
2.37u² = 46.506u
Divide both side by u
2.37u² / u = 46.506u / u
2.37u = 46.506
Divide both side by 2.37
u = 46.506 / 2.37
u = 19.6 cm
Thus, the lens should be held at a distance of 19.6 cm.
Write down 2 differences between electrical conductors and electrical insulators.
Answer:
electrical conductors help electric current to pass through it
electrical conductors are usually made of any metal
electrical insulator don't help electric current to pass through it
electrical insulators are made of non metals
hope it helped you
Explanation:
conductors allows free flow of electrons from one atom to another.
insulators restrict free flow of electrons
conductors allow electrical energy to pass through them
insulators do not allow electrical energy to pass through them
One of the ways in which a coin operated vending machine checks to make sure that the coins fed to it are genuine is to roll them past a strong magnet. Group of answer choices Coins made of a good conductor will slow down as they roll past the magnet. Coins made of a good conductor will speed up as they roll past the magnet. Only coins made of magnetic materials such as iron will be affected by the magnet. The coins will become magnetized and thus can easily be sorted.
Answer:
Coins made of a good conductor will slow down as they roll past the magnet.
Explanation:
Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.
One of the ways in which a coin operated vending machine checks to make sure that the coins fed to it are genuine is to roll them past a strong magnet. As such, coins made of a good conductor will slow down as they roll past the magnet due to the force of attraction that exists between the magnet and the coin (metal).
This ultimately implies that, the magnet tends to attract the coin to itself and as such slowing down the motion of the coin. Similarly, if it's a fake coin, it simply means it would be a bad conductor and as such it will roll fast past the strong magnet.
It is much more difficult to move a dresser full of clothes than an empty dresser
Answer:
Newton's Law 2
Hope this helps!
According to Newton's first law of motion when will an object at rest begin to move
Answer:
When acted upon by a force.
Explanation:
"If a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force."
What is the work done by gravity on a 4 kg ball
a. as it goes from point B to point A?
b. As it goes from point A to C?
(horizontal distance between A and B is 8 m; between B and C is 3.2 m)
Answer:
a. Work done = 313.92 Joules
b. Work done = 439.49 Joules
Explanation:
Work done = Force x distance
Where: Force = mass x gravity
Thus,
Work done = Force x gravity x distance
The earth's acceleration to gravity = 9.81 m/[tex]s^{2}[/tex].
a. The work done as it goes from B to A can be determined as;
work done = 4 x 9.81 x 8
= 313.92 Joules
b. The distance between A and C is the total horizontal distance covered from A to C.
i.e 8 + 3.2 = 11.2 m
The work done as the ball goes from point A to C can be determined as:
work done = 4 x 9.81 x 11.2
= 439.488
work done = 439.49 Joules
Explain how radioactive decay works for measuring the absolute age of ancient objects.
Answer: Radioactive decay is the breakdown of a material into stable isotopes which are used for determining the age of the ancient material.
Explanation:
The radioactive decay is a natural process in which an ancient or old material whether in the form of rock, object or fossil break down into elements. Carbon 14 is an unstable isotope which decays to produce stable elements, the dating procedure uses these stable elements and the rate of decay of the isotopes to determine the age of absolute ancient of the objects but exact age cannot be determined just an approximation can be accepted.
What are four reasons why it is important to apply for entry at tertiary institutions while you are still at grade 11
Answer:
Explanation:
The main reason for doing this is to get the attention of the tertiary institutions early. There are thousands of students that apply to these institutions every year, depending on the strictness of the acceptance of these institutions it may or may not be difficult for you to enter. Applying while at grade 11 gives you more chances of getting in as you are catching the attention of the institution and showing a high level of interest. This also allows you more chances to enter, since if you are denied you can try again next year. Aside from this, some institutions have specific requirements, applying early can allow you to know what you are missing as they will tell you if you get denied. You can then work towards obtaining these requirements and apply next year.
Can anyone help me with this question please
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No links.
Answer:
Answer is B
Explanation:
Answer:
B. Frequency
Explanation:
12. Which of the following statements is accurate?
A. If an object's velocity is changing, it's experiencing either acceleration or deceleration.
B. If an object's velocity decreases, then the object is accelerating
C. If an objects said to be decelerating, its velocity must be increasing,
D. If an object's velocity remains constant, its acceleration must be increasing.
Answer:
Option (a) is correct
Explanation:
The acceleration of an object is defined as the rate of change of velocity. Mathematically, it can be written as :
[tex]a=\dfrac{v-u}{t}[/tex]
Where
v and u are final and initial velocity
It is clear that if there is some change in velocity, it means the object is experiencing either acceleration or deceleration. Hence, the correct option is (a).
Answer:
a
Explanation:
When forming a ion, oxygen will have what charge?
Answer:
it will have a charge of -2
Explanation:
Se lanza un objeto hacia arriba y en 3.2 segundos cae. Determinar la altura máxima a la que llegó y la velocidad con la que choca con el piso.
Indicate the direction of the magnetic force. A positive charge travels to the right of the page through a magnetic field that points into the page. Which way does the magnetic force point?
A. Up along the page
B. Down along the page
C. Left
D. Right
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Explanation:
A. Up along the page
Using the law of the right hand