What property do the following elements have in common? Li, C, and F A) They are poor conductors of electricity. B) Each element participates in covalent bonding. C) They all exist in the same phase at room temperature. D) The valence electrons for each element is located in the same energy level.
Answer: Option (D) is the correct answer.
Explanation:
The given elements Li, C and F are all second period elements. So, when we move from left to right across a period then there occurs increase in number of valence electrons as there occurs increase in total number of electrons.
So, it means more electrons are added to the same energy level.
Thus, we can conclude that a property of valence electrons for each element is located in the same energy level is common in the given elements.
Answer:
the answer is d
Explanation:
i did the usa test prep
The record of an earthquake obtained from a seismic instrument is a(n) ________.
Answer:
Explanation:
It’s a SESMOGRAPH
There are 206 _____ in the human body that work together to form the _______ system.
The human body contains 206 bones which collectively make up the skeletal system, providing structure, protection, and enabling movement. Bones also play vital roles in the production of blood cells and storing nutrients.
Explanation:There are 206 bones in the human body that work together to form the skeletal system. This system offers protective support for the body's organs, creates blood cells, stores minerals, and enables movement. For instance, the skull shields the brain, the ribs protect the heart and lungs, the spine safeguards the spinal cord, and the pelvis shields the reproductive and digestive organs. The skeletal system and muscular system are the reasons we can move.
Bones also generate our blood cells in the bone marrow, and store some types of minerals such as calcium and phosphate.
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The first step to using ecology to solve environmental problems is to
a. ban the burning of fossil fuels.
b. close businesses that pollute.
c. use alternative fuels.
d. identify the problem.
Answer: d. identify the problem
Explanation:
Identify the problem is the correct option this is because of the fact that the natural environment may experience disturbance due human intervention like burning of fossil fuels, pollution or due to natural calamity like earthquakes, landslides and volcanic eruptions. To solve these problems detection of problem should be the first step that can lead to mitigation. These problems exerts negative influence over the ecosystem hence are detectable.
The density of gold is 19.3 g/cm3. A piece of gold displaces 2 mL of water. The specific gravity of gold is:
A.19.3
B.38.6
C.9.6
D.0.10
Answer:
A) 19.3
Explanation:
As we know that specific gravity is defined as the ratio of weight of the object and weight of the water displaced by the object
so it is given by
[tex]Specific \gravity = \frac{weight \: of \: object}{weight \: of \: water\: displaced}[/tex]
now we have
weight of the object = (density)(volume)g
weight of object = [tex](19.3 g/cm^3)(2 mL)g[/tex]
now weight of the liquid displaced is given by
weight of water displaced = [tex](1 g/cm^3)(2 mL)g[/tex]
now we have
specific gravity = [tex]\frac{(19.3)(2mL)g}{(1)(2 mL)g}[/tex]
specific gravity = 19.3
Use the table below to identify four substances that undergo a physical change if the temperature is reduced from 50oc to -50oc. what is the physical change that takes place in each case.
Some enterprising physics students working on a catapult decide to have a water balloon fight in the school hallway. the ceiling is of height 3.6 m, and the balloons are launched at a velocity of 11 m/s. the acceleration of gravity is 9.8 m/s 2 . at what angle must they be launched to just graze the ceiling?
[tex]50^\circ[/tex] angle above the horizontal.
Step by Step Solution :
Given :
Launch speed = 11 m/sec
Height of the ceiling = 3.6 m
[tex]\rm g = 9.8\;m/sec^2[/tex]
Calculation :
Let [tex]\theta[/tex] be the launch angle, measured above the horizontal.
Vertical component of initial speed is
[tex]\rm v = 11sin\theta[/tex]
We know that
[tex]\rm v^2 - u^2=2as[/tex]
[tex]\rm 11^2 sin^2\theta - 2\times9.8\times 3.6 =0[/tex]
[tex]\rm sin\theta = 0.7636[/tex]
[tex]\rm \theta = sin^-^10.7636[/tex]
[tex]\theta = 49.8^\circ \approx 50^\circ[/tex]
[tex]50^\circ[/tex] angle above the horizontal they launched to just graze the ceiling.
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You are a scientist trying to develop a technology that can be used to power wrist watches. Which type of electromagnetic wave would be most useful to investigate?
A force does +190 j of work when it acts on a moving object and its direction is in the same direction as the object's displacement. how much work does this force do when the angle between it and the object's displacement is 56°? (assume the displacement is the same.)
What diameter is the sun by the scale used? a0 mm
Select the statement that correctly describes how light travels. (2 points) Select one:
a. Light cannot travel in a vacuum because it travels slower when the light source is moving.
b. Light cannot travel in a vacuum because the light source is stationary.
c. The speed of light, traveling in a vacuum, will not change if the light source is moving.
d. Light traveling in a vacuum changes speeds when the light source moves.
The correct answer is c
n order to climb a steep hill on a bicycle, a rider shifts to the lowest gear. The lowest gear has the greatest mechanical advantage because it
Which is not an assumption about particles in a gas according to the kinetic theory?
The motion of one particle is unaffected by other particles unless the particles collide.
The forces of attraction among particles keep the particles close together.
Under ordinary conditions, forces of attraction between particles can be ignored.
A volcano erupted on an island. The entire plant community was destroyed and the island was covered with grey ash. Slowly, lichens and mosses started growing on the island. They helped in the process of soil formation and later other plants started growing too.
Final answer:
Primary succession occurs when new land is formed, and pioneer species like lichens and mosses help break down the rock and create soil.
Explanation:
Primary succession occurs when new land is formed, such as after a volcanic eruption. The pioneer species, like lichens and mosses, help break down the rock and create soil. As the soil develops, other plants can grow and replace the pioneer species. This process eventually leads to an equilibrium state with a diverse set of organisms.
please help!!!
Which of the following is an example of chemical weathering?
1. Frost wedging
2. Animal activity
3.Oxidation
4. Abrasion
Out of
Frost wedging Animal activity Oxidation; and Abrasion,I'd say 3. Oxidation.
1) Which of the following alternative energy sources is NOT inexhaustible?
tidal energy
solar energy
geothermal energy
wind energy
2) Which of the following is a problem associated with the increased use of nuclear energy?
cost of building sage nuclear facilities
major hazards involved in nuclear waste disposal
concern over the possibility of a serious nuclear accident
all of the above
3) One problem with wind energy as a major source of electricity is ________.
it is nonrenewable
it causes major air polution
it does not work at night
the expense of large tracts of the land in populated areas
Your most reliable answer my friend would be 1. Wind 2. All of the above 3. The expense of large tracts of land in populated areas
Which of the following is defined as displacement over change in time?
A. Speed
B. Acceleration
C. Velocity
D. Displacement
Uranus has an orbital period of 84.07 years. In two or more complete sentences, explain how to calculate the average distance from Uranus to the sun and then calculate it.
The formula is p^2=a^3
Answer:
Average distance from Uranus to the sun, a = 2.88 billion km
Explanation:
It is given that,
Orbital period of Uranus, T = 84.07 years = 2.65 × 10⁹ s
We have to find the average distance from Uranus to the sun. It can be calculated using Kepler's third law as :
[tex]T^2\propto a^3[/tex]
or [tex]T^2=\dfrac{4\pi^2}{GM}a^3[/tex]
Where
T is orbital period
a is the average distance from Uranus to the sun
G is universal gravitational constant
M is mass of sun, [tex]m=1.98\times 10^{30}\ kg[/tex]
[tex]a^3=\dfrac{T^2GM}{4\pi^2}[/tex]
[tex]a^3=\dfrac{(2.65\times 10^9)^2\times 6.67\times 10^{-11}\times 1.98\times 10^{30}}{4\pi^2}[/tex]
[tex]a^3=2.34\times 10^{37}\ m[/tex]
[tex]a=2.86\times 10^{12}\ m[/tex]
a = 2.88 billion km
Hence, this is the required solution.
What did William Herschel discover that Isaac newton didn't
William Herschel discovered the planet Uranus, mapped the structure of the Milky Way, and was the first to detect infrared radiation, all of which were discoveries not made by Isaac Newton.
William Herschel made several significant discoveries that Isaac Newton did not, owing to the advancement of scientific knowledge and technology in Herschel's time. One of Herschel's most noteworthy achievements was the discovery of the planet Uranus in 1781. This discovery was the first identification of a new planet in the modern era and extended the known boundaries of our solar system at the time.
Furthermore, Herschel's contributions to astronomy also include the recognition of the Milky Way's structure. In 1785, using his custom-built large reflecting telescope, he conducted an extensive star count along with his sister Caroline. Through this, he mapped the shape of the Milky Way Galaxy, deducing that it has a disk-like structure with the sun near its central region. Prior to Herschel's observations, the full extent and shape of the galaxy were not understood.
If a star is less than 10 parsecs from us, what can we say about how its apparent and absolute magnitudes compare? hints they will be the same number. more information is needed to make a judgment. absolute magnitude will be the larger number. apparent magnitude will be the larger numbe
A cartoon shows two friends watching an unoccupied car in free fall after it has rolled off a cliff. one friend says to the other "It goes from zero to sixty miles per hour in about three seconds." is this statement correct?
The statement is not correct because the velocity of the car in a free fall after 3 seconds is 29.4 m/s while the assumed velocity of the friend is 26.82 m/s.
The given information;
assumed initial velocity of the car, u = o assumed final velocity of the car, v = 60 miles per hourtime of motion, t = 3 secondsThe velocity of an object under the influence of gravity;
v = u + gt
where;
g is acceleration due to gravity = 9.8 m/s²
Convert the given final velocity in mph to m/s;
[tex]v = 60 \ \frac{miles}{hour} \times \frac{1609.34 \ m}{1 \ mile} \times \frac{1 \ hour}{3600 \ s} = 26.82 \ m/s[/tex]
Determine if the assumed final velocity will be equal to actual velocity in 3 seconds after the motion.
v = 0 + (3 x 9.8)
v = 29.4 m/s
Thus, the statement is not correct because the velocity of the car in a free fall after 3 seconds is 29.4 m/s while the assumed velocity of the friend is 26.82 m/s.
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obesity refers to gradual weight gain as a person grows older
4. You bought a block of cheddar from the grocery store. If you cut a small piece and a large piece from the same block of cheese, will they have the same density?
Answer: They will have same density
Explanation:
Density is defined as the mass contained per unit volume.
[tex]Density=\frac{mass}{Volume}[/tex]
Density is characteristic of a compound and thus remains constant at fixed temperatures.
A small piece would have lesser amount and will occupy a smaller volume. Similarly a larger piece would have larger amount and will occupy a larger volume.
Thus the ratio of mass and volume will remain fixed or constant and the density will be same for smaller and larger piece.
What is energy? differentiate between potential and kinetic energy?
Energy is the capacity to do work or cause motion, existing as either potential energy, which is stored, or kinetic energy, which is the energy of motion. Potential energy can be elastic, gravitational, or chemical, while kinetic energy is directly involved in movement and changes in motion.
Energy is the capacity to do work or cause motion. It exists in various forms which can be generally categorized into potential energy and kinetic energy. The fundamental difference between these two is that potential energy is stored energy based on an object's position, condition, or composition, whereas kinetic energy is the energy of motion, the energy that an object possesses due to its movement.
In kinetic energy, an object is in motion, like a moving car. In potential energy, the energy is stored, like a stretched spring. For example, a ball thrown in the air has kinetic energy when moving upward and potential energy at the highest point of its trajectory.
Potential energy can be further differentiated into various types, such as elastic potential energy found in stretched or compressed springs and rubber bands, gravitational potential energy which is due to an object's position relative to Earth or another celestial body, and chemical potential energy which is stored in chemical bonds and released during chemical reactions.
Kinetic energy is expressed as [tex]KE = \frac{1}{2} mv^2[/tex], where 'm' stands for mass and 'v' for velocity. Examples of kinetic energy include the movement of machinery, electricity flow, wind, and water currents. It's the active form of energy, that is directly involved in causing changes and creating motion.
When an object's potential energy is converted into kinetic energy, it begins to move and work is done. This occurs without the creation or destruction of energy, adhering to the law of conservation of energy or the first law of thermodynamics.
What is vigorous activity?
A any activity or exercise performed most days of the week, preferably daily
B any activity or exercise that ranges in intensity from heavy-to-maximum exertion
C any activity that ranges in intensity from light-to-borderline-exertion
Any activity or exercise that ranges in intensity from heavy-to-maximum exertion is vigorous activity.
What is vigorous activity?Vigorous activities require the highest amount of oxygen consumption to complete the activity.
Exercise that is performed with a lot of effort, also known as vigorous exercise or high-intensity exercise, causes a markedly elevated heart rate and fast breathing. Exertion is regarded severe to extremely hard with this activity, making it challenging to speak in complete sentences. Activities like singles tennis, cycling, and running are typically categorized as vigorous.
Hence vigorous activity is any activity or exercise that ranges in intensity from heavy-to-maximum exertion. So, option (B) is correct.
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You throw a 20-n rock vertically into the air from ground level. you observe that when it is a height 15.4 m above the ground, it is traveling at a speed of 24.2 m/s upward.
I believe there are two things which we asked to find here:
1. its speed just as it left the ground
2. find its maximum height
Solutions:
1. We use the formula:
ΔKE = - ΔPE
where KE is kinetic energy = ½ mv^2, and PE is potential energy = m g h, Δ = change
Therefore:
½ m (v2^2 – v1^2) = m g (h1 – h2)
at initial point, point 1: h1 = 0, v1 = ?
at final point, point 2: h2 = 15.4 m, v2 = 24.2 m/s
½ (24.2^2 – v1^2) = 9.8 (0 – 15.4)
585.64 – v1^2 = -301.84
-v1^2 = 887.48
v1 = 29.8 m/s
So the rock was travelling at 29.8 m/s as it left the ground.
2. The maximum height (hmax) reached is calculated using the formula:
v1^2 = 2 g hmax
Rewriting in terms of hmax:
hmax = v1^2 / 2 g
hmax = (29.8)^2 / (2 * 9.8)
hmax = 45.3 m
Therefore the rock reached a maximum height of 45.3 meters.
This high school physics question discusses the principles of kinematics and energy conservation. Given the speed and height of a rock thrown vertically upwards, it asks to determine the initial speed of the rock. We calculate this using the given values and the formula for kinetic energy & gravitational potential energy conservation, getting the initial velocity as approximately 16.88 m/s.
Explanation:The subject of this question pertains to physics, specifically the application of the principles of kinematics and energy conservation in studying projectile motion. Neglecting air resistance, the speed of a projectile (like a rock) thrown vertically upwards at a certain height from the ground can be calculated using energy considerations. From the given, the rock is starting from ground level with a certain velocity upwards and it is observed that at a height of 15.4 m, its speed is 24.2 m/s. Let's denote the initial speed when the rock was thrown as v0.
Using the equation v = √(2gh + v0²), where g is the acceleration due to gravity (9.8 m/s²) and h is the height (15.4 m), we can find the initial velocity of the rock. Plugging in the known values, we get v0 as √[(24.2 m/s)² - 2*(9.8 m/s²)×15.4 m] = √(585.64-301.6) m/s = √284.04 m/s = 16.88 m/s.
This calculation tells us the initial speed required to achieve the observed height and speed. This information can be crucial in physical scenarios involving projectiles.
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Why is the wavelength of a moving soccer ball not detectable to the naked eye?
This is mainly because the wavelength of a moving soccer ball is extremely small so it is not detectable to the naked eye. The wavelength of a moving soccer ball is much smaller than what the human eye can pick up, so it cannot be seen.
The wavelength of a moving soccer ball is too small to be detected due to the ball's large mass. This tiny wavelength is immeasurable and has no noticeable effect on the soccer ball's behavior. The de Broglie wavelength is significant only for particles with small mass or high velocity.
The concept of wavelength in matter is explained by the de Broglie wavelength, which is only noticeable for particles with very small mass and/or very high velocity.
For macroscopic objects like a soccer ball, which have a large mass, the wavelength is extremely small. To illustrate, even if a soccer ball were moving at a high speed, its wavelength would still be smaller than the size of an atom, making it impossible to detect with our senses or any known instruments.In summary, while matter waves are a fundamental concept in physics, the wavelengths associated with large objects such as a soccer ball are so minuscule that they have no observable impact on the motion of the ball.1. Which of these is necessary for a reasonable order-of-magnitude estimate of the speed of a falling object?
a. Round all numbers to the nearest whole number.
b. Have a correct and exact value for the distance of the fall.
c. Use numbers for the time and distance of the fall that are reasonable even if inexact.
d. Assume that any falling object takes about a second to reach the ground
Mechanical (sound) waves are unable to travel through a vacuum, such as through space, but radio waves are transmitted to earth from satellites. how is this possible?
a.radio waves are electromagnetic waves.
b.satellites are located within our atmosphere.
c.radio waves are very high energy mechanical waves.
d.radio waves are changed to gamma rays for transmission.
When a 85 kg man sits on the stool, by what percent does the length of the legs decrease? assume, for simplicity, that the stool's legs are vertical and that each bears the same load?
Final answer:
To determine the percent decrease in the stool's leg length under a man's weight, additional information such as the original leg length and material properties are required. Using Hooke's law or relevant formulas, we could then calculate the strain and convert it to a percentage.
Explanation:
To calculate by what percent the length of the legs of a stool decrease when an 85 kg man sits on it, we need certain information that is not provided in this scenario, such as the original length and material properties of the stool's legs (e.g., the Young's modulus if we assume the legs are cylindrical rods), as well as the assumption that each leg bears the same load.
Without this additional information, we cannot calculate the exact percentage change in length. If this information were available, we would use Hooke's law, which is commonly used to determine the deformation caused by applying a force on a spring. We would also consider the modulus of elasticity for materials that are not springs. The change in length (ΔL) divided by the original length (L0) gives the strain, which can be multiplied by 100 to find the percentage deformation.
The length of the stool's legs decreases by approximately 0.00083% when a 85 kg man sits on it.
Calculating Deformation of Stool Legs
To determine the percent decrease in the length of the legs of a stool when a 85 kg man sits on it, we can use the formula for linear deformation:
[tex]\Delta L = (F \times L) / (A \times Y)[/tex]
Where:
[tex]\Delta L[/tex] is the change in length.F is the force applied.L is the original length of the legs.A is the cross-sectional area of the legs.Y is the Young's modulus of the material.Assuming each of the stool’s four legs equally shares the weight of the man, the force per leg due to the man’s weight is:
[tex]F = (85 kg \times 9.81 m/s^2) / 4 = 208.42 N[/tex]
Let’s assume the original length (L) of the legs is 0.5 meters and the radius of the legs is 0.02 meters. The cross-sectional area (A) can be calculated using the formula for the area of a circle: [tex]A = \pi \times r^2[/tex]
Thus, the cross-sectional area is:
[tex]A = \pi \times (0.02 m)^2 = 1.2566 \times 10^{-3} m^2[/tex]
Assuming the legs are made of a material with Young's modulus (Y) of [tex]2 \times 10^{10} N/m^2[/tex], the change in length (ΔL) is:
[tex]\Delta L = (208.42 N \times 0.5 m) / (1.2566 \times 10^{-3} m^2 \times 2 \times 10^{10} N/m^2) = 4.15 \times 10^{-6} meters[/tex]
To find the percent decrease in length:
[tex]\text{Percent Decrease} = (\Delta L / L) \times 100 = (4.15 \times 10^{-6} m / 0.5 m) \times 100 = 0.00083\%[/tex]
Therefore, the length of the stool's legs decreases by approximately 0.00083% when the 85 kg man sits on it.