The first periodic table of elements Mendeleev created contained only 70 elements. True or false?

Answers

Answer 1

Explanation:

FALSE

The first periodic table of elements Mendeleev created contained 63 elements.


Related Questions

. Four bars of metal A, B, C and Dare tested for magnetism. B attracts both A and C but not D. D does not attract A, B or C. A and C sometime attract one another and sometimes repel one another. What conclusion can you draw about? (a) Bar A (b) Bar B (c) Bar D​

Answers

Answer:

a. Bar A is a magnet

b. Bar B is a metal or magnetic material

c. Bar D is a non-magnetic material

Explanation:

a. Bar A

Since B attracts both A and C, it shows that A and C are both magnetic. So, it is either B and A are magnets or B and C are magnets or A and C are magnets. Also, since A and C sometime attract one another and sometimes repel one another, it means that they attract when their poles are opposite and repel when their poles are negative. This show that both A and C are magnets. Thus, A is a magnet.

b. Bar B

Since B is attracted to both A and C and we know that both A and C are magnets, it implies that B is a magnetic material. Since it does not repel either A or C.

c. Bar D

Since D does not attract A, B or C, D is a non-magnetic material. Since, only a magnetic material can be attracted to magnets and we have established that both A and C are magnets and that B is magnetic. Since D is not also attracted to B, it implies that D is thus non-magnetic.

The plane of a5cm*8cm rectangular loop of wire is parallel to a 0.19T magnetic field the loop carries a current of 6.2 A. What torque acts on aloop? What is the magnetic moment of the loop?

Answers

Answer:

Torque; τ = 4.712 × 10^(-3) J

Magnetic moment; M = 0.0248 J/T

Explanation:

Torque is gotten from the formula;

τ = BIA

Where;

B is magnetic field

I is current

A is area

We are given;

B = 0.19T

I = 6.2A

Rectangle dimensions = 5cm by 8cm = 0.05m by 0.08m

Thus;

Area; A = 0.05m × 0.08m = 0.004 m²

Thus;

τ = 0.19 × 6.2 × 0.004

τ = 4.712 × 10^(-3) J

Formula for the magnetic moment is given by;

M = IA

M = 6.2 × 0.004

M = 0.0248 J/T

Multi-part question If a galaxy moving away from the Earth has a speed of 1000 km/s and emits 656 nm light characteristic of hydrogen (the most common element in the universe). What wavelength would we observe on the Earth

Answers

Answer:

658.2 nm

Explanation:

Since the galaxy is moving at relavitistic speed, we use the equation for relativistic Doppler shift of light.

So, the wavelength of light observed on the Earth is λ

λ = λ'([tex]\sqrt{\frac{ 1 + \frac{v}{c} }{1 - \frac{v}{c} } }[/tex])

where  λ' = wavelength of light emitted by galaxy = 656 nm, v = speed of galaxy = 1000 km/s (positive since the galaxy is moving away from the Earth) and c = speed of light = 300000 km/s

So, substituting the values of the variables into the equation, we have

λ = λ'(√[{1 + (v/c)}/(1 - (v/c)]

λ = 656 nm(√[{1 + (1000 km/s/300000 km/s)}/(1 - (1000 km/s/300000 km/s)]

λ = 656 nm(√[{1 + 1/300}/(1 - 1/300]

λ = 656 nm(√[{(300 + 1)/300}/{(300 - 1)/300}]

λ = 656 nm(√[{(301)/300}/{(299)/300}]

λ = 656 nm(√[301/299])

λ = 656 nm(√1.0067)

λ = 656 nm × 1.0033

λ = 658.19 nm

λ ≅ 658.2 nm

So, the wavelength observed on Earth is 658.2 nm

resistances is inversely proprtional to___of the conductor​

Answers

Answer:

resistances is inversely proportional to the area of cross section of the conductor

Explanation:

The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area.

hope this helps you

have a nice day:)

Two boys X and Y each have the same total weight
and are standing on soft ground.
Which boy is more likely to sink into the soft ground and
why?
boy more
likely to sink
pressure on soft
ground
А
Х
larger than Y
B
Х
smaller than Y
C
Y
larger than X
D
Y
smaller than X​

Answers

Answer:

the child with the smallest area will be the one who sinks

Explanation:

The child who will sink to the ground is the one who exerts the greatest pressure on the ground, even though the force, which in this case is equal to the weight, is equal.

Pressure is defined by

           P = F / A

in this case the strength of the children is their weight

           F = W

           P = W / A

therefore the pressure changes are in the area of ​​contact with the ground, the child with the smallest area will be the one who sinks

An open winding in an electric motor means that ____. A. a wire in a winding is broken B. the centrifugal switch to the start winding is open C. the winding is making contact with the motor frame D. one winding is making contact with another winding

Answers

Answer:

A. a wire in a winding is broken.

Explanation:

An electric circuit can be defined as an interconnection of electrical components which creates a path for the flow of electric charge (electrons) due to a driving voltage.

Generally, an electric circuit consists of electrical components such as resistors, capacitors, battery, transistors, switches, inductors, etc.

Basically, an electric circuit is considered to be open when there's a broken continuity (broken path), which causes no current to flow through the circuit.

On the other hand, a closed circuit is one in which there's a flow of current due to a complete electrical path.

On a related note, an open winding in an electric motor means that a wire in a winding is broken.

how does she hold a newspaper while reading without using the lens? why?​

Answers

bananas are grrrrrreat

Which two statements are true about a system?

a)A system is a group of objects analyzed as one unit.
b)Energy that moves across system boundaries is conserved.
c)There’s only one way to define the boundaries of a system.
d)All systems are made by humans.

Answers

A and c

Because it defines the boundaries of the system

Luis rushes 40m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60s.

What is Luis’s average speed over the 60s?
What is Luis average velocity over the 60s?

Answers

1. The average speed of Luis over the 60 s is 1.33 m/s

2. The average velocity of Luis over the 60 s is zero.  

1. The average speed can be calculated with the following equation:

[tex] S = \frac{d}{t} [/tex]

Where:

d: is the total distance traveled

t: is the total time = 60 s

The total distance can be calculated by the sum of the distance traveled to the truck (40 m) and the distance traveled to his home (the same 40 m), as follows:

[tex] d = 40 m + 40 m = 80 m [/tex]

So, the average speed is:

[tex] S = \frac{d}{t} = \frac{80 m}{60 s} = 1.33 m/s [/tex]

Hence, Luis's average speed over the 60 s is 1.33 m/s.

 

2. Now, the average velocity is a vector given by:

[tex]v = \frac{\Delta x}{\Delta t} = \frac{x_{f} - x_{i}}{t}[/tex]

Where:

[tex]x_{f}[/tex]: is the final distance traveled (the way to his home) = 40 m

[tex]x_{i}[/tex]: is the initial distance traveled (the way to his truck) = 40 m

Δt: is the total time = t = 60 s

Given that Luis in his journey, returns to the same starting point (his house), the total displacement is zero, and so the average velocity is also zero:                              

[tex]v = \frac{x_{f} - x_{i}}{t} = \frac{40 m - 40 m}{60 s} = 0[/tex]

Therefore, Luis's average velocity over the 60 s is zero.  

You can find more about average speed and average velocity here: https://brainly.com/question/12322912?referrer=searchResults

I hope it helps you!                                              

As shown in the figure below, Luis rushes 40 m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60 s.

Answer:

What is Luis’s average velocity over the 60 s period?

Answer: 0 m/s

What is Luis’s average speed over the 60 s period?

Answer: 1.33  m/s

True or False. A compound is formed when two or more elements are combined to make a new substance with
its own properties


True
Fase

Answers

I believe that the answer is true

Hope this helps :))

PLS MARK AS BRAINLY PLSSSS

An airplane starts from rest and undergoes a uniform acceleration of 10.8 m/s^2 for 16.7 s seconds before leaving the ground. What is its displacement?

Answers

Answer:

3012.012m

Explanation:

s=it +1/2(10.8)(16.7)^2

Is velocity ratio of a machine affected by applying oil on it? Explain with reasons.

Answers

Answer:

when it comes to machines being Rusty oil is like the root loosener

You are pulling a sled using a horizontal rèpe, as shown in the diagram. The rope pulls the sled. exerting a force of 50 N to the right. The snow exerts a friction force of 30 N on the sled to the left. The mass of the sled is 50 kg.

Please help me with this

Answers

Answer:

Explanation:

From your other post, the complete question is:

"You are pulling a sled using a horizontal rèpe, as shown in the diagram. The rope pulls the sled. exerting a force of 50 N to the right. The snow exerts a friction force of 30 N on the sled to the left. The mass of the sled is 50 kg.

Find the sum of the force on the sled.

Determine the acceleration of the sled .

If the sled has an initial velocity 2m/s to the right, how fast will it be traveling after 5 seconds?

"

Given the rope exerting a force of 50 N to the right and the snow exerts a friction force of 30 N to the left, the sum of forces

= 50 - 30

= 20N to the right

The mass of sled is 50 kg and force = mass * acceleration.

Acceleration = Force / mass

= 20 / 50 = 0.4 m/s^2 to the right

If the sled has an initial velocity 2m/s to the right, after 5 seconds it will be traveling at initial velocity + acceleration * time

= 2 + 0.4*5

= 4 m/s to the right

Answer:

Explanation:

net force = applied force - friction force

= 50-30

= 20N to right

acceleration = net force/mass

= 20/50

= 2/5m/s tp right

final velocity = initial velocity + acceleration*time

= 2+2/5*5

= 4m/s to right

at what angle should the circular road be banked so that a car running at 50 km per hour be safe to go round the circular from of 200m radius​

Answers

Answer:

Mark brainliest please

answer is 5.5 degrees

Explanation:

Given,

Speed of car (v) = 50km/hr = 50×1000/60×60 m/s

Radius of circle (r) = 200m

Banking angle (θ) =?

we know ,

tanθ = v^2/rg

or , tanθ = (50×1000/60×60)^2/200×10 = 0.0965

∴ θ = tan-1(0.0965) = 5.5°

A monatomic gas is measured to have an average speed of 1477 m/s. If the
total amount of the gas is 2 mol (which equates to a mass of 0.008 kg), what
is the approximate temperature of the gas? (Recall that the equation for
kinetic energy due to translation in a gas is KEtranslational = 1 mv2 = 3 nRT,
2
and R = 8.31 J/(mol-K).)
2

Answers

Answer:

The temperature of the gas is 350.02 K.

Explanation:

The average speed is related to the temperature as follows:

[tex] \bar v = \sqrt{\frac{3RT}{M}} [/tex]   (1)

Where:

[tex] \bar v [/tex]: is the average speed = 1477 m/s

R: is the gas constant = 8.31 J/(K*mol)                                                  

T. is the temperature =?

M: is the molar mass

First, let's find the molar mass:

[tex] M = \frac{m}{n} [/tex]

Where:

m: is the mass of the gas = 0.008 kg

n: is the number of moles = 2 mol

[tex] M = \frac{m}{n} = \frac{0.008 kg}{2 mol} = 0.004 kg/mol [/tex]

Hence, by solving equation (1) fot T we have:

[tex] T = \frac{\bar v^{2}*M}{3R} = \frac{(1477 m/s)^{2}*0.004 kg/mol}{3*8.31 J/(K*mol)} = 350.02 K [/tex]

Therefore, the temperature of the gas is 350.02 K.

I hope it helps you!            

a. A man of 100 kg mass is standing on the surface of the earth of mass 6 × 1024 kg and
radius 6400km. Calculate the gravitational force between them. [Ans: 977.05 N]

Answers

Answer:

m1=100kg

m2=6×10^24kg

r=6400km

G=6.6×10^-11

F=?

as we know that

F=G m1.m2/r²

F=6.6×10^-11×100×6×10^24/(6400)²

F=6.6×10^-11×6×10^26/4.096×10^7

F=6.6×10^-11×1.465×10^19

F=9.67×10^8N

A ball of mass 1.0 kg is rolling due west at 30 m/s. A second ball of mass 2.0 kg moving due north at 6.0 m/s collides with the first ball and they stick together. What is the magnitude of the momentum of the two-ball system immediately after collision

Answers

Answer:

the magnitude of the momentum of the two-ball system immediately after collision is 32.31 kg.m/s

Explanation:

Given;

mass of the first ball, m₁ = 1.0 kg

mass of the second ball, m₂ = 2.0 kg

initial velocity of the first ball, v₁ = 30 m/s due west

initial velocity of the second ball, v₂ = 6 m/s due north

From the principle of conservation of linear momentum;

the total momentum before collision = total momentum after collision

The westward momentum of the first ball, = m₁v₁ = 1 x 30 = 30 kg.m/s

The northward momentum of the second ball = m₂v₂ = 2 x 6 = 12 kg.m/s

The resultant momentum of the two balls;

R² = 30² + 12²

R² = 1044

R = √1044

R = 32.31 kg.m/s

Therefore, the magnitude of the momentum of the two-ball system immediately after collision is 32.31 kg.m/s

A) Give 3 examples of forces that are pulls and 3 examples that are pushes. b) For each example you give, state an approximate value for the size of the force.

Answers

Answer:

Explanation:

Force is defined as the push or pull which changes or tries to change the position, state of motion and the shape of the object.

(A) The examples of push are:

To push a chair on the floor, to push the car when it is stopped due to some problem, to push book on the table.

The examples of pull are :

To pull a chair towards you, to pull a string in a game of top, to pull the string in a gym.

(B) To push a chair or a book, the force required is small as compared to the to push a car.

To pull a chair or the string of top is less than the force to pull the string in gym.

The capacity of an RD bottle is 100 cc and its mass is 45 g. Find the mass of the bottle when it is filled with a liquid of density 600 kg/m3.​

Answers

Answer:

The capacity of an RD bottle is 100cc and its mass is 45g. Find the mass of the bottle when it is filled with a liquid of density 600kg/[tex]m^{3}[/tex]

 

EXPLANATION:

100cc=100[tex]cm^{3}[/tex]

density of liquid=600Kg/  =0.6gm/

 so mass of 100cc liquid will be m=d×V=0.6×100=60gm

So mass of bottle filled with liquid will be bottle+liquid=45gm+60gm=105gm  

Answer is 105gm.

state any two effects of gravitational force ​

Answers

Answer:

The effect of gravity extends from each object out into space in all directions, and for an infinite distance. However, the strength of the gravitational force reduces quickly with distance. Humans are never aware of the Sun's gravity pulling them because the pull is so small at the distance between the Earth and Sun.

Answer:

The Earth's gravitational force accelerates objects when they fall. It constantly pulls, and the objects constantly speed up.

Explanation:

a car moves at a speed of 40km/h. it is stopped by applying brake which produce a uniform acceleration of-0.5m/s^2. how much distance will it move before coming to stop ?

Answers

Answer:

Explanation:

We first need to convert the 40 km/h to m/s. Going by the fact that 40 has only 1 significant figure in it, 40 km/h = 10 m/s. The rest of the values are in their proper labels. We will use the equation:

[tex]v^2=v_0^2+2a[/tex]Δx where the final velocity is 0 because the car is coming to a stop at the end; the initial velocity is 10 m/s, the acceleration (or, rather, deceleration) is -.5 m/s/s, and our unknown which is displacement. Filling in:

[tex]0=(10)^2+2(-.5)[/tex]Δx and solving for Δx:

Δx = [tex]\frac{-100}{2(-.5)}[/tex] which ends up being simply that

Δx = 100 m

Global warming is threatening polar bear habitats and the bears' way of life. If trends continue, predict what will become of the polar bear in the next 10,000 years. Will it adapt or become extinct? Defend your answer.

Answers

it will become a stink. It will become extinct because if people keep doing what you’re doing it will get no better.

Bear will become extinct due to global warming.

What is greenhouse gas?

The gases which get easily trapped inside the glasses and increase the temperature of the atmosphere causing the global warming level to increase overall.

Global warming is threatening polar bear habitats and the bears way of life. If global warming continues, predict what will become of the polar bear in the next 10,000 years

Thus, bear will extinct.

Learn more about greenhouse gas.

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how is one standard kilogram defined in SI system?​

Answers

Answer:

One standard kilogram is define as the mass of platinium iridium cylinder having equal diameter and height kept at the particular condition of international bureo of weigh and measure sevre near paris.

PLEASE HELP!!

A set of water waves travels at 20.0 m/s , and 5.0 waves pass you in 4.0 s. What is the wavelengths of the waves?

a. 0.25 m

b. 8.0 m

c. 0.20 m

d. 4.0 m

Answers

Answer:

Explanation:

[tex]\lambda\\[/tex] = v/f

^That is the formula we are going to use.

Now, we were given the speed (v), which is 20.

Now we need to find frequency, in order to solve for the wavelength.

Frequency is the amount of waves in a fixed unit of one second, meaning our F value is the value of 5 divided by 4.

5/4 = 1.25

Therefore our F is 1.25

Now lets plug it in

[tex]\lambda\\[/tex] = v/f

[tex]\lambda\\[/tex] = 20/1.25

[tex]\lambda\\[/tex] = 16

Conversion:

[tex]\lambda\\[/tex] = 8

During the collision of a big truck with a small passenger carGroup of answer choicesthe force from the truck on the car is always much bigger than the force from the car on the truck.the force from the truck on the car may be smaller than, greater than, or equal to the force from the car on the truck.the force from the truck on the car is always much smaller than the force from the car on the truck.the force from the truck on the car is always equal to the force from the car on the truc

Answers

Answer:

The force from the truck on the car is always equal to the force from the car on the truck.

Explanation:

According to Newton's third law; action and reaction are equal and opposite. Hence, when the big truck and small passenger car are involved in a collision, we expect that the force from the truck on the car is always equal to the force from the car on the truck. The forces on the car and the truck are equal in magnitude but opposite in direction.

This follows directly from Newton's third law of motion hence the answer above.

What acceleration is produced on a mass of 200g, when a force of 10N is exerted on it?​

Answers

Answer:

f=ma......10N=0.2a....=50m/s

Answer:

here,

force = mass× acceleration

10 = 0.2 kg × a

or, 10/0.2=a

or, a = 50km/h^2

is the required ans .

Please help! Will mark Brainliest

Answers

Explanation:

I think it is the third image as marked in the diagram I kept above because as we know first class levers have the fulcrum between the force and the load

state Pascal's principle of pressure . please help due tomorrow​

Answers

Answer:

Pascal's law says that pressure applied to an enclosed fluid will be transmitted without a change in magnitude to every point of the fluid and to the walls of the container.

Explanation:

The pressure at any point in the fluid is equal in all directions.

Explanation:

According to pascal law ,Force applied on bulk of water in a container will be distributed to all molecules of water...

Annie has a soccer ball and a cake ball she kicks each ball with the same Force the soccer ball accelerates at 3 m per second squared and the kickball accelerates at 5 m per second squared use Newton's law to describe why the kickball has a greater acceleration

Answers

Answer: The acceleration will be greater in the kickball than the soccer ball since the kick ball has a smaller mass and provided they are acted upon with equal force magnitude.

Explanation:

We can prove this by substituting with numerical values.

Say the force she kicked both balls with was 30 N. The mass of the soccer ball is 10kg and the mass of the kickball is 6kg.

Applying Newtons Second Law, F = ma

For the soccer ball:

30 = 10a
a = 30/10
a = 3

For the kickball:

30 = 6a
a = 30/6
a = 5

Hence the kickball will travel with a greater acceleration given the same force is acted upon and has a smaller mass than the soccer ball

Hope this helps, brainliest would be appreciated :)

A 43-kg child sits in a massless swing. With what horizontal force must the seat be pulled so that the ropes form an angle of 35o with respect to the vertical

Answers

Fx = 295.4N

180°-90°-35°= 55°

F= m(a)

Fy = 43kg(9.81m/s²)

Fy = 421.83N

tan(55°) = 421.83N/Fx

Fx = 421.83N/tan(55°)

Fx = 295.3685458N

What are horizontal and vertical forces?

Each component describes the influence of that chain in the given direction. The vertical component describes the upward influence of the force upon Fido and the horizontal component describes the rightward influence of the force upon Fido.

What direction is friction force?

The kinetic frictional force is always in the direction opposite to the velocity of the object.

Learn more about  horizontal component, refer

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