The Periodic Table Question 3 of 10 Based on the trend in valence electrons across periods for main-group elements, how many valence electrons does fluorine (F) have? O A. 4 B. 7 O C. 6 D. 5 SUBT​

Answer:

option 2

Explanation:

you are very welcom

Answer:

25km

Explanation:

The person runs 15km Northward

 Turns around and runs 10km southward

The distance is the length of path covered by the person running.

This is given as:

 Distance  = Distance North + Distance South

Distance  = 15km + 10km  = 25km

Answer:

25km

Explanation:

cant explain but ik

The thing same about a particle as gas, liquid, or solid is its chemical composition.

Matter exists in three different states: solid, liquid, and gas. By examining the configuration of their particles, it is possible to understand why they have various qualities. Theoretically, at this temperature, particles move slowly and have the least amount of energy.

Phase refers to the material's actual state. To pay attention to is the word physical. Only physical means can change the state of matter. You can make a physical change if energy is added (by raising the temperature) or subtracted (by freezing things).

The chemical composition of matter same about a particle as gas, liquid or solid.

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Answer:

11.025m

Explanation:

In this question there is no vertical velocity,

t= 1.5s

Height of platform=h

From Newton equation

s = ut + 1/2gt^2

But there is no vertical velocity,

Hence,

Then u=0

h = 0 + 1/2 x 9.8 x (1.5)^2

h = 11.025m

Answer: macroscopic outputs

Explanation:

When fireworks explode, sound and light are produced. These are examples of macroscopic outputs. Because, explosion from fireworks is an exothermic process which releases massive heat energy to the surroundings.

Exothermic reaction are those which evolve heat energy to the surroundings.  The change in enthalpy of the reaction is negative here. Whereas, in an endothermic reaction energy is absorbed by the reactants.

Exothermic reactions sometimes results in massive explosion. The heat energy released to the surroundings from the fire works is macroscopic level.

The small scale process or quantity that cannot be measured using normal scales are called microscopic units. Therefore, the sound, light, and heat from the explosion all are macroscopic outputs.

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Answer:

Ver la explicación a continuación.

Explanation:

En física estas siglas significan movimiento rectilíneo uniforme, es decir es el tipo de movimiento donde la velocidad es constante. La velocidad no cambia con el tiempo.

Este tipo de movimiento se puede describir con la siguiente ecuación.

[tex]x=x_{0}+v*t[/tex]

Donde:

x = posición final [m]

xo = posición inicial [m]

v = velocidad [m/s]

t = tiempo [s]

Answer:

High in the atmosphere, air pressure decreases. ... A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. As the air rises, the water vapor within it condenses, forming clouds and often precipitation.

Explanation:

Answer:

4200 J/°C/kg

Explanation:

The formula for heat transfer is given by :

Q= m*c*ΔT  where;

Q= heat transferred = 6930 J

m=mass of the liquid = 0.330 kg

c= specific heat capacity=?

ΔT = 25-20 = 5.0°C

Applying the values in the formula as;

Q= m*c*ΔT

6930 = 0.330 * c * 5

6930 = 1.65 c

6930/1.65 = c

4200 = c

c= 4200 J/°C/kg

The age of the sample can be determined using the first order equation of the nuclear decay. The age of the parent isotope here is 45 years.

Unstable radioactive nuclei undergo nuclear decay to produce more stable nuclei with more life time. The time required to decay half of the initial amount of a material is called its half life.

The half life of a sample is related with the decay constant k as follows:

k = 0.693/t1/2

Given that, t1/2 = 15 years

k = 0.693/15 = 0.0462 yr⁻¹

The first order equation of the decay process is written as:

k = 1/t ln w0/wt

where w0 is the initial amount and wt be the amount after time t.

then t = 1/k ln w0/wt

Given that, the sample was decayed to one eighth of the initial amount .

t = 1/k ln 8

 = 1/0.0462 ln 8

 = 45 years.

Therefore, option C is correct.

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Velocity of sound travels faster in solids than in liquids, and faster in liquids than in gases because "the density of solids is higher than that of liquids, meaning that the particles are closer together."

Answer:

Explanation:

Due to the fact that sound is caused by vibrations, it's more noticeable in liquid because the vibrations may cause ripples in the liquid

Answer:

[tex]1.5\cdot 10^{-5}\:\mathrm{N}[/tex]

Explanation:

Newton's Law of Gravitation is given as:

[tex]F=G\frac{m_1m_2}{r^2}[/tex], where [tex]G[/tex] is gravitational constant [tex]6.67\cdot 10^{-11}[/tex] and [tex]r[/tex] is the distance between their centers of mass.

Therefore, the gravitational force between them is:

[tex]F=6.67\cdot 10^{-11}\frac{55\cdot40}{0.1^2}= \fbox{$1.5\cdot 10^{-5}\:\mathrm{N}$}[/tex] (two significant figures).

Answer:

98.0N

Explanation:

Answer:

1m/s²

Explanation:

Given parameters:

Initial velocity  = 2m/s

Final velocity  = 4m/s

Time of chase  = 2s

Unknown:

Acceleration = ?

Solution:

Acceleration is the rate of change of velocity with time;

 A = [tex]\frac{v - u }{t}[/tex]  

A is the acceleration

v is the final velocity

u is the initial velocity

t is the time taken

      A  = [tex]\frac{4 - 2}{2}[/tex]   = 1m/s²

Explanation:

what is time in this question

can you please show a picture

Answer:

6

Explanation:

From the given question, since a total of 12 V was obtained from the battery which is made up of a number of cells with each producing 2.0 V.

Assuming that the cells have a very low internal resistance, then;

minimum number of electric cells in the car battery = [tex]\frac{total voltage from the cells}{individual voltage of the cells}[/tex]

                                          = [tex]\frac{12}{2}[/tex]

                                          = 6

Thus, the minimum number of electric cells in the car battery is 6.

This implies that the addition of 6 cells which has 2.0 V supply in the battery produces a total of 12 V. Provided that the cells have a very low internal resistance.

Answer:

I believe you are correct but we just started this unit

Explanation:

Answer:

28.1 m/s

Explanation:

[tex]u_x[/tex] = Initial velocity of the fish = 1.52 m/s

y = Height of the bird = 40 m

[tex]a_y[/tex] = Acceleration in y axis = [tex]9.81\ \text{m/s}^2[/tex]

[tex]u_y[/tex] = Initial velocity in y axis = 0

[tex]y=u_yt+\dfrac{1}{2}a_yt^2\\\Rightarrow 40=0+\dfrac{1}{2}\times 9.81t^2\\\Rightarrow t=\sqrt{\dfrac{40\times 2}{9.81}}\\\Rightarrow t=2.86\ \text{s}[/tex]

[tex]v_y=u_y+a_yt\\\Rightarrow v_y=0+9.81\times 2.86\\\Rightarrow v_y=28.057\ \text{m/s}[/tex]

The final velocity in x direction will remain the same as the initial velocity as there is no acceleration in the x direction [tex]u_x=v_x=1.52\ \text{m/s}[/tex]

Resultant velocity is given by

[tex]v=\sqrt{v_x^2+v_y^2}\\\Rightarrow v=\sqrt{1.52^2+28.057^2}\\\Rightarrow v=28.1\ \text{m/s}[/tex]

The fish is moving at a velocity of 28.1 m/s when it hits the water.

Answer:

d = 4[m]

Explanation:

Torque in physics is defined as the product of force by distance. This way you can use the following equation to calculate the torque.

[tex]T=F*d[/tex]

where:

T = torque [N*m]

F = force [N]

d = distance [m]

Now replacing in the equation above.

[tex]84=21*d\\\\d= 4[m][/tex]

Answer:

a) A force of 367718.75 newtons is needed to get the full airplane safely in the air.

b) The empty airplane would need a runway of 1828.571 meters.

Explanation:

a) This problem can be solved by using the Work-Energy Theorem, which states that work needed by the airplane to get minimum speed is equal to its change in translational kinetic energy, both measured in joules. The resulting formula is presented below:

[tex]F\cdot \Delta s = \frac{1}{2}\cdot m \cdot (v_{f}^{2}-v_{o}^{2})[/tex] (1)

Where:

[tex]F[/tex] - Minimum net force, measured in newtons.

[tex]\Delta s[/tex] - Runway length, measured in meters.

[tex]m[/tex] - Mass of the airplane, measured in kilograms.

[tex]v_{o}[/tex], [tex]v_{f}[/tex] - Initial and final speeds of the airplane, measured in meters per second.

If we know that [tex]m = 350000\,kg[/tex], [tex]v_{o} = 0\,\frac{m}{s}[/tex], [tex]v_{f} = 82\,\frac{m}{s}[/tex] and [tex]\Delta s = 3200\,m[/tex], then the minimum net force needed by the airplane to get itself safely in the air:

[tex]F = \frac{m\cdot (v_{f}^{2}-v_{o}^{2})}{2\cdot \Delta s}[/tex]

[tex]F = \frac{(350000\,kg)\cdot \left[\left(82\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right]}{2\cdot (3200\,m)}[/tex]

[tex]F = 367718.75\,N[/tex]

A force of 367718.75 newtons is needed to get the full airplane safely in the air.

b) If we know that [tex]m = 200000\,kg[/tex], [tex]v_{o} = 0\,\frac{m}{s}[/tex], [tex]v_{f} = 82\,\frac{m}{s}[/tex] and [tex]F = 367718.75\,N[/tex], then the length of the runway is:

[tex]\Delta s = \frac{m\cdot (v_{f}^{2}-v_{o}^{2})}{2\cdot F}[/tex]

[tex]\Delta s = \frac{(200000\,kg)\cdot \left[\left(82\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right]}{2\cdot (367718.75\,N)}[/tex]

[tex]\Delta s = 1828.571\,m[/tex]

The empty airplane would need a runway of 1828.571 meters.

Answer:

Fscos63

Explanation:

Given that a horizontal pole is attached to the side of a building. There is a pivot P at the wall and a chain is connected from the end of the pole to a point higher up the wall. There is a tension force F in the chain. What is the moment of the force F about the pivot P?

Taking the moment from the pivot point P, that means the moment at point p = 0

Then, if we consider the weight mg of the pole, according to the principle of equilibrium : sum of the upward forces equal to the sum of the downward forces.

Therefore, mg = Fsinø ....... (1)

Also, taking moment at point P

Let the length of the pole = s

The length of the weight of the pole = 1/2 S

Fscosø = mgs/2

The distance s will cancel out

2Fcosø = mg ...... (3)

Substitute mg in equation 1 into equation 3

2fcosø = fsinø

F will cancel out

Tanø = 2

Ø = tan^-1(2)

Ø = 63.4 degree

The moment of force F about pivot point P will be

Moment = force × distance

Moment = Fcos63 × S

Moment = Fscos63

Answer:

Gravity is an ever present force, and therefore acceleration is guaranteed to happen at every single one of those points (and in fact, everywhere in the universe).

On top of that, friction will be present in all four spots (friction with the rails, with the air, with the axles, etc.), and friction is a perfectly acceptable force that will cause acceleration, slowing the roller coaster down.

So the correct answer is every single point, regardless of what answer the teacher expects.

The object will be moving faster if the acceleration and velocity are pointing in the same direction. The object will also slow down if the acceleration is pointing in the opposite direction as the velocity.

When an object's speed, direction of motion, or both change, it accelerates. Even while it may appear to be virtually immediate in some circumstances, such as when a golf ball is struck by a club or during car collisions, changes in an object's speed are always continuous.

Since gravity is a constant force, acceleration will unavoidably occur at each of those locations and throughout the whole universe.

Therefore, In addition, there will be friction at all four locations—friction with the axles, the air, the rails, etc.—and friction is a completely normal force that will accelerate the roller coaster, slowing it down.

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Answer:

I guess that the atoms are:

Protons:     6     8    5    2    12    12

Neutrons:  8     8     5   3     13    14

Now, two atoms are isotopes if they share the same number of protons (so both atoms are the same element) but they have a different number of neutrons.

From the given options, the only two that have the same number of protons but a different number of neutrons are:

Protons 12, neutrons 13

and

Protons 12, neutrons 14.

These two are isiotopes.

Answer:

weight at height = 100 N .

Explanation:

The problem relates to variation of weight  due to change in height .

Let g₀ and g₁ be acceleration due to gravity , m is mass of the object .

At the surface :

Applying Newton's law of gravitation

mg₀ = G Mm / R²

At height h from centre

mg₁ = G Mm /h²

Given mg₀ = 400 N

400 = G Mm / R²

400 = G Mm / (6400 x 10³ )²

G Mm = 400 x (6400 x 10³ )²

At height h from centre

mg₁ =  400 x (6400 x 10³ )²/ ( 2 x 6400 x 10³)²

= 400 / 4

= 100 N .

weight at height = 100 N

Answer:

Im not fully corrrect but I would say C

Explanation:

The principles which allow aircraft to fly are also applicable in car racing. The only difference being the wing or airfoil shape is mounted upside down producing downforce instead of lift. The Bernoulli Effect means that: if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid. The wing of an airplane is shaped so that the air moving over the top of the wing moves faster than the air beneath it. Since the air pressure under the wing is greater than that above the wing, lift is produced. The shape of the Indy car exhibits the same principle. The shape of the chasis is similar to an upside down airfoil. The air moving under the car moves faster than that above it, creating downforce or negative lift on the car. Airfoils or wings are also used in the front and rear of the car in an effort to generate more downforce. Downforce is necessary in maintaining high speeds through the corners and forces the car to the track. Light planes can take off at slower speeds than a ground effects race car can generate on the track. An Indy ground effect race car can reach speeds in excess of 230 mph using downforce. In addition the shape of the underbody (an inverted wing) creates an area of low pressure between the bottom of the car and the racing surface. This sucks the car to road which results in higher cornering speeds.

The total aerodynamic package of the race car is emphasized now more than ever before. Teams that plan on staying competitive use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus of their efforts is on the aerodynamic forces of negative lift or downforce and drag. The relationship between drag and downforce is especially important. Aerodynamic improvements in wings are directed at generating downforce on the race car with a minimum of drag. Downforce is necessary for maintaining speed through the corners. Unwanted drag which accompanies downforce will slow the car. The efficient design of a chassis is based on a downforce/drag compromise. In addition the specific race circuit will place a different demand on the aerodynamic setup of the car.

A road course with low speed corners, requires a car setup with a high downforce package. A high downforce package is necessary to maintain speeds in the corners and to reduce wear on the brakes. This setup includes large front and rear wings. The front wings have additional flaps which are adjustable. The rear wing is made up of three sections that maximize downforce.

The speedway setup looks much different. The front and rear wings are almost flat and are used as stabilizers. The major downforce is found in the shape of the body and underbody. Drag reduction is more critical on the speedway than on other circuits. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern in the speedway setup. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of downforce is especially pronounced in highspeed corners. A race car traveling at 200 mph. can generate downforce that is approximately twice its own weight.

Generating the necessary downforce is concentrated in three specific areas of the car. The ongoing challenge for team engineers is to fine tune the airflow around these areas.

Answer:

52.802

Explanation:

"Significant figures" in Mathematics refer to the digits that give accuracy to the value of a measurement. There are specific rules when it comes to determining the significant figures. For example, all non-zero digits are considered significant and zeroes located in-between non-zero numbers are significant. In the number given above, the digit "0" is located between "8" and "1," therefore, it is significant. All the digits above are significant.

The problem is only asking for "five" significant figures. We can do this by counting from the left to the right. By this means, we know that the number will be rounded off to the nearest thousandths, which is "1." The number after 1 is 5, which means that 1 digit will be added to number 1, thus, making the digit into "2." The last digit (5) will then be removed.

Explanation:

five significant of 52.8015=52.801 ..

Answer:

[tex]\mathrm{(a)\:}32,000,000\:\mathrm{Ns},\\\mathrm{(b)\:}390,000\:\mathrm{N}[/tex]

Explanation:

The impulse-momentum theorem states the impulse on an object is equal to the change in momentum of that object. Momentum is given by [tex]p=mv[/tex]. Since mass is constant, the train's change in momentum is:

[tex]\Delta p=m\Delta v=750,000\cdot42=31,500,000=\fbox{$32,000,000\:\mathrm{Ns}$}[/tex](two significant figures).

Impulse is also given as [tex]\Delta p = F\Delta t[/tex], where [tex]F[/tex] is the average force applied and [tex]\Delta t[/tex] is change in time. Since [tex]t[/tex] is given as [tex]80\mathrm{s}[/tex], we have the following equation:

[tex]F\Delta t=\Delta p\\\\F=\frac{\Delta p}{\Delta t},\\\\F=\frac{31,500,000}{80},\\\\F=393,750=\fbox{$390,000\:\mathrm{N}$}[/tex](two significant figures).