Please I need help with this ❤️ ?

Explanation:

FALSE

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

Answer:

please do write it in english

Answer:

The electrons come from the free electrons in wool which contains moisture or other forms of additives that creates impurity centers which causes the wool to be electrically conductive

Explanation:

Wool which is mixed with certain substances, conducts electricity in a manner similar to the wool-water system that give rise to centers of impurities where electrical conduction takes place

The ability to conduct electricity is related to the presence of free electrons on a material. Therefore, when a balloon, which is an insulator, is rubbed with wool, some of the mobile electrons on wool, which is also an insulator without the presence of substances that aid its electrical conductivity, are transferred to the balloon, thereby making the balloon to be negatively charged

Encontramos que la distancia recorrida en los primeros 9 segundos es 288 metros.

Los datos dados son:

El cuerpo tiene una rapidez inicial de 5 m/s

El cuerpo tiene una aceleración de 6 m/s^2

Queremos calcular la distancia recorrida durante los primeros 9 segundos de movimiento.

Lamentablemente no contamos con los gráficos ni las tablas, así que se procede a obtener las ecuaciones de movimiento.

La aceleración será:

a(t) =  6m/s^2

Para la ecuación de la velocidad tenemos que integrar la ecuación de arriba, obteniendo:

v(t) = (6m/s^2)*t  + v0

Donde v0 es la rapidez inicial, que conocemos es igual a 5 m/s, así tenemos:

v(t) = (6m/s^2)*t  + 5m/s

Para la ecuación de la posición debemos integrar nuevamente, así obtendremos:

p(t) = (1/2)*(6m/s^2)*t^2  + (5m/s)*t + p0

Donde la p0 es la posición inicial, la cual podemos definir como p0 = 0m

p(t) = (3m/s^2)*t^2  + (5m/s)*t

Para encontrar la distancia recorrida en los primeros 9 segundos, simplemente debemos remplazar t por 9s en la ecuación de posición:

p(9s) =  (3m/s^2)*(9s)^2  + (5m/s)*9s = 288 m

Si querés aprender más sobre ecuaciones de movimiento, podés leer:

https://brainly.com/question/17123407

Explanation:

Given that,

Mass of an object, m = 250 g = 0.25 kg

Spring constant, k = 48 N/m

The amplitude of the oscillation, A = 5.42 cm = 0.0542 m

1. At equilibrium,

ma = kx

Where

a is the acceleration of the object

So,

[tex]a=\dfrac{kx}{m}\\\\a=\dfrac{48\times 0.0542}{0.25}\\\\a=10.4\ m/s^2[/tex]

2. The maximum speed of the object is :

[tex]v=A\omega\\\\v=A\sqrt{\dfrac{k}{m}}\\\\v=0.0542\times \sqrt{\dfrac{48}{0.25}}\\\\v=0.75\ m/s[/tex]

Hence, this is the required solution.

Answer:

Explanation:

mass of linebacker, m = 111 kg

initial velocity, u = 1.9 m/s

mass of quarterback, m' = 82 kg

initial velocity, u' = 3 m/s

(a) Let they are moving in the same direction, the velocity is v after collision.

Use conservation of momentum

m u + m' u' = (m + m') v

111 x 1.9 + 82 x 3 = (111 + 82) v

v = 2.4 m/s

Let they are moving in opposite direction, the velocity is v after collision.

Use conservation of momentum

m u - m' u' = (m + m') v

111 x 1.9 - 82 x 3 = (111 + 82) v

v = - 0.18 m/s

option E

3m/s square

hope it helped u

Answer: [tex]N43.2[/tex]

Explanation:

Given

Power consumption of bulb and water are [tex]60\ W[/tex] and [tex]240\ W[/tex]

If the Devices are on for four hours

Total power of devices [tex]60+240=300\ W[/tex]

Energy consumed for 4 hours is

[tex]\Rightarrow 300\times 4=1200 Wh\\\Rightarrow 1.2\ kWh[/tex]

For 30 days it is [tex]1.2\times 30=36\ kWh[/tex]

Cost for 30 days [tex]36\times 1.2=43.2\ N[/tex]

Explanation:

Relative density=density of liquid÷density of water

1.25=x ÷ 1000

x=1.25 × 1000

x=1250kgm^-3

Answer:

Equivalent

A conversion factor is a ratio of equivalent measures

Answer:

C

Explanation:

Answer:

Please find attached, the required wave drawn with MS Excel

Explanation:

Functions that represent waves is given as follows

A general form of the wave equation is A·sin(B·x) + D

Where;

B = 2·π/T

T = The period of the wave = 1/f

D = The vertical shift of the wave = 0

A = The amplitude of the wave = 1 for sine wave

v = The wave velocity

λ = The wavelength of the wave

f = The frequency of the wave

v = f·λ

At constant v, λ ∝ 1/f  

∴ λ ∝ T

Where T = 3, we have;

B = 2·π/T

∴ B = 2·π/3

Therefore, we have the wave with an amplitude of 1 cm, and wavelength, 3 cm, given as follows

y = sin((2·π/3)·x)

Plotting the above wave with MS Excel, we can get the attached wave

Answer:

λ = 610.6 nm

Explanation:

We are given;

Separation distance; d = 0.195 mm = 0.195 × 10^(-3) m

Interference pattern distance; D = 4.95 m

Width of the two adjacent bright interference; β = 1.55 cm = 1.55 × 10^(-2) m

Formula for the Fringe width is;

β = Dλ/d

Where;

λ is laser's wavelength

Thus;

λ = (d × β)/(D)

λ = (0.195 × 10^(-3) × 1.55 × 10^(-2))/4.95

λ = 610.6 × 10^(-9) m

λ = 610.6 nm

Explanation:

The acceleration g varies by about 1/2 of 1 percent with position on Earth's surface, from about 9.78 metres per second per second at the Equator to approximately 9.83 metres per second per second at the poles.

Answer:

D. crystalline solid that conducts current under certain conditions

Explanation:

Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.

Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.

Answer:

A dicot is a flowering plant that has one seed leaves. The monocot plants have a single cotyledon. Maize only has one cotyledon in their seed, so it's a monocot. Seeds having two Cotyles are mainly called a Dicot. A pea is a dicotyledonous plant, the seed (the pea itself) has two halves, cotyledons, hence dicot being 2.

Explanation:

One or more of the cotyledons are the first to appear from a germinating seed. Based on the number of cotyledons, botanists classify flowering plants (angiosperms) into :

a) plants with one embryonic leaf, termed monocotyledonous (monocots).

b) plants with two embryonic leaves, termed dicotyledonous (dicots).

Helpful Link:

https://www.vedantu.com/question-answer/in-pea-caster-and-maize-the-number-of-cotyledons-class-11-biology-cbse-5f626a17e5bde9062ff6d2a3

Answer:

6.34×10⁹ seconds

Explanation:

Applying,

V = d/t............. Equation 1

Where V = speed plate, d =  distance covered by the plate, t = time it takes the plate to travel

make t the subject of the equation

t = d/V............ Equation 2

From the question,

Given: d = 5 cm/yr = (5×3.154×10⁻⁹) = 1.577×10⁻⁸ m/s,  d = 100 meter

Substitute these values into equation 2

t = 100/1.577×10⁻⁸

t = 6.34×10⁹ seconds

Hence the time it takes the the plate to travel is 6.34×10⁹ seconds

[tex]\sf\underline{Solution:}[/tex]

Here , the density of the material is 4g cm³ but it is not given in CGS system.

$\sf{As\:we\:know\:that:}$

$\sf\bold{Density=}$ $\sf\dfrac{Mass}{Volume}$

$\space$

[tex]\sf{Now,according \: to \:the\:question:}[/tex]

$\sf\small{Density\:of\:the\:material=4}$ $\sf\dfrac{g}{cm^2}$

$\space$

$\sf{It\:is\:given\:that:}$

In the system of units the mass is 100gram.

$\space$

Hence,

$\sf{The\:mass\:unit\:for\:4g=}$ $\sf\dfrac{4}{100}$ $\sf{units}$

$\space$

In the system of units,the length is 10cm.

Henceforth,

$\sf\small{The\:length \:for\:1cm\:units=}$ $\sf\dfrac{1}{10}$ $\sf{units}$

$\space$

☆ Substitute the required values in the given formula-

$\sf\purple{Density=}$ $\sf\dfrac\purple{Mass}\purple{volume}$

$\space$

$\sf\underline\bold{Density\:of\:the\:material:}$

= $\sf\dfrac{4/100}{1/10^3}$ $\sf\bold{units}$

$\space$

= $\sf\dfrac{4/100}{1/1000}$ $\sf\bold{units}$

$\space$

= $\sf\dfrac{4000}{100}$ $\sf\bold{units}$

$\space$

$\sf\underline\bold\blue{=40\:units}$

$\sf\small{Therefore,option\:2nd\:is\:correct!}$

_______________________________

Answer:

He is suffering from hypermetropia.

Explanation:

There are some defects of vision.

Longsightedness of hypermetropia : It is the defect of vision in which the person is not able to see the nearby objects clearly but can see the far off objects clearly. This is due to the elongation of size of eye ball. It is cured by using convex lens of suitable focal length.

Nearsightedness or Myopia : It is the defect of vision in which a person is not able to see the far off objects clearly but can see the nearby objects clearly. It is due to the contraction in the size of eye ball. It is cured by using concave lens of suitable focal length.

So, Hideki is suffering from hypermetropia. So, he should use the convex lens of suitable focal length.  

Answer:

in order to know the length of something

please mark me as brainiest p

Explanation:

Magnetic lines of force are closed curves. C) Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.

Answer:

68.6 m/s^2

Explanation:

1 g = 9.8 m/s^2

so

7 g × 9.8m/s^2 = 68.6

Answer:

57

Explanation:

Answer:

v = 333.26 m/s

Explanation:

Given that,

The frequency of the tuning fork, f = 262 Hz

It produces the third resonance position above a closed air column that is 1.59 m in length.

We need to find the speed of sound in tuning fork. Let it is f. The third resonance position corresponds to the fifth harmonic of the closed air column. The wavelength in third resonance is given by :

[tex]\lambda=\dfrac{4}{5}L\\\\=\dfrac{4}{5}\times 1.59\\\\=1.272\ m[/tex]

The speed of sound is :

[tex]v=f\lambda\\\\=262\times 1.272\\\\=333.26\ m/s[/tex]

So, the speed of sound is 333.26 m/s.

Answer:

The speed of sound is 555.44 m/s.

Explanation:

frequency of third resonance position, f''' = 262 Hz

length of pipe, L = 1.59 m (closed)

Let the speed is v.

The frequency of third resonance in closed organ pipe is

[tex]f''' =\frac{3 v}{4 L}\\\\262 = \frac{3 v}{4\times 1.59}\\\\v = 555.44 m/s[/tex]

Answer:

Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.

Machines are not 100% efficient because some of the work done by a machine is used to overcome friction

Answer:

Remember the relation:

Speed*Time = Distance.

We can estimate that the speed at which an earthquake "moves", in the surface, is:

S = 6km/s  (this is a low estimation actually)

Then if the wave is detected 12.5 minutes after the earthquake, we know that it traveled for 12.5 minutes before reaching the detector.

So we know the speed of the wave and the time it took to reach the detector, then we can use the equation:

Speed*Time = Distance.

to find the distance.

First, we should write the time in seconds

we know that:

1 min = 60 s

then:

12.5 min = 12.5*(60 s) = 750 s

Then, the wave traveled with a speed of 6 km/s for 750 seconds until it reached the detector, then the distance that it traveled is:

(6km/s)*750s = 4500 km

The distance between the detector and the site of the quake is around 4500 km.

Answer: two uses of a wedge can be to tighten things as well as to lift things.

Explanation: because that is some things wedges (a mechanical tool) can do.

Answer:

am I the only one seeing blink