Which phrase describes a scientific law?
A. A statement that matter cannot be created or destroyed
B. A claim that experiments cannot verify whether matter has been
destroyed
O C. An explanation for why matter cannot be created or destroyed
D. A prediction of how much matter exists in the universe
SUBMIT
In

Explanation:

13+x=43>2x

13+x=43>2x+43>2x

13+x=86>4x

x-4x=86-13

3x=73

x=73/3

x=24.333

x=24.4

Answer:

B

Explanation:

because when the air rises the density increases

We want to predict what will happen to the density of the air on the surface of the Earth when it warms up.

We will see that the correct option is D: "It decreases, then increases"

We know that the temperature of a given object (in this case a mass of air) is related to the kinetic energy of the particles that conform it.

As the temperature increases, the kinetic energy also increases, thus, the amount of motion of each particle increases, thus, the volume of the object increases.

Now remember that:

density = Mass/Volume.

So if the volume of something increases, we will see that the density decreases (as the volume is in the denominator).

Then if the temperature of the air increases, we will see that the density of the air in the surface decreases.

But it does not end there, as only the air near the surface suffers this change of density, we will have a denser mass of air (colder air) above it. And because it is denser (has more mass in the same volume) we can say that it is heavier.

Then eventually the hot air will rise, and the cold air will fall down, thus the density of the air in the surface increases again, as the colder and denser air comes near the surface.

This is one way of how wind currents are born.

Concluding we can see that the correct option is D: "It decreases, then increases"

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Answer:

inertia

Explanation:

Answer: rotational force

Explanation:

Torque is the twisting force which cause rotation and the axis of rotation is the point at which the object rotates.

Torque is a rotational force as it leads to the rotation of an object about an axis. Force simply means a pull or push. When an unbalanced ball acts on a force, the ball, the ball will be moved towards the linear motion.

Then, the unbalanced force that is acting in the ball produces torque which causes the ball's rotational motion.

The Torque is best described as a rotational force.

It is the force that causes an object to rotate. Torque is measured in Newton-meters (N-m).

An example of a force is the force of gravity. When you hold a ball in your hand, the force of gravity is pulling down on the ball.

However, the ball is not rotating because the force of gravity is being counteracted by the force of your hand pushing up on the ball.

An example of a torque is when you use a wrench to loosen a bolt. When you apply force to the wrench, you are creating a torque that is trying to turn the bolt.

The more force you apply, the greater the torque.

Torque is not the same as rotational velocity. Rotational velocity is the rate at which an object is rotating. It is measured in radians per second (rad/s).

Torque is also not the same as rotational energy.

Rotational energy is the energy that an object has due to its rotation.

It is measured in joules (J).

Torque is also not the same as rotational power. Rotational power is the rate at which rotational energy is transferred. It is measured in watts (W).

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Answer:

FALSE

Explanation:

The Answer Is - 0.58 Kilogram's

Hope This Help's

• Answer:

0.58 kg

• Explanation:

1 kg = 1000 g

580 g = 0.58 kg

Answer: Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. ... During the 1930s Bohr helped refugees from Nazism.

Answer:

0.0552 m/s²

Explanation:

Given:

Δx = 69.0 m

v₀ = 0 m/s

t = 50 s

Find: a

Δx = v₀ t + ½ at²

69.0 m = (0 m/s) (50 s) + ½ a (50 s)²

a = 0.0552 m/s²

Answer:

5000 m/s

Explanation:

The three ways a car can accelerate are change in velocity, change in direction, or both.

The rate of velocity change concerning time is known as acceleration. The acceleration of the object is;

[tex]\rm a = \frac{v-u}{t}[/tex]

Here,

a is the acceleration

v is the final velocity

u is the initial velocity

t is the period

The three ways a car can accelerate are as follows;

a)Change in velocity.

b)Change in direction

c)Change in both velocity and direction.

Hence, the three ways a car can accelerate are change in velocity, change in direction, or both.

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Answer:

The value is [tex]v_s = 1.394 \ m/s[/tex]

Explanation:

From the question we are told that

The frequency of the second player is [tex]f_2 = 490 \ Hz[/tex]

The beat frequency is [tex]f_b = 2.0 \ Hz[/tex]

The speed of sound is [tex]v_s = 343 \ m/s [/tex]

Generally the frequency of the note played by the first player is mathematically represented as

[tex]f_1 = f_2 + f_b[/tex]

=> [tex]f_1 = 490 + 2.0 [/tex]

=> [tex]f_1 = 492 Hz[/tex]

From the relation of Doppler Shift we have that

[tex]f_1 = \frac{ f_2 (v+ v_o )}{v-v_s }[/tex]

Here [tex] v_o\ is\ the\ velocity\ of\ the\ observer\ with\ value\ 0 \ m/s [/tex]

So

[tex]492 = \frac{ 490 (343+0 )}{343 -v_s }[/tex]

=> [tex]v_s = 1.394 \ m/s[/tex]

Answer:

   ρ = 4.4 10⁻⁸ Ω m

Explanation:

For this exercise let's start by finding the value of the resistance using Ohm's law

          V = I R

           R = V / I

The voltage is related to the electric field

          V = E L

let's substitute

          R = E L / I

          R = 8.2 10⁻² / 20  

          R = 4.1 10⁻³ L

now we can use the resistance relation

          R = ρ L / A

the area of ​​a circular wire is

          A = π r² = π d² / 4

         ρ = R π d² / (4 L)

let's calculate

        ρ = (4.1 10⁻³ L) π 0.0037² / (4 L) = (4.1 10⁻³) π 0.0037² / (4)

        ρ = 4.4 10⁻⁸ Ω m

The resistivity of the wire is 4.4 10⁻⁸ Ω m.

We know that;

V = I R

R = V / I

The voltage  the electric field can be connected using the formula;

V = E L

Hence;

R = E L /I

R = 8.2 10⁻² / 20  

R = 4.1 10⁻³ L

For resistivity;

R = ρ L / A

the area can be obtained from;

A = π r² = π d² / 4

ρ = R π d² / (4 L)

ρ = (4.1 10⁻³ L) π 0.0037² / (4 L) = (4.1 10⁻³) π 0.0037² / (4)

ρ = 4.4 10⁻⁸ Ω m

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Answer:

a)  I = 0.0198 kg m² ,  b)    I = 21.85 kg m²

Explanation:

For this exercise we will use the definition of moment of inertia

        I = ∫ r² dm

For body with high symmetry they are tabulated

sphere  I = 2/5 m r²

bar with respect to  center of mass I = 1/12 m L²

let's calculate the mass of each body

bar

        ρ = m / V

        m = ρ V

        m = ρ l w h

where we are given the density of the bar rho = 32840 kg / m³ and its dimensions 1 m, 0.8 cm and 4 cm

        m = 32820 1 0.008 0.04

        m = 10.5 kg

Sphere

       M = ρ V

       V = 4/3 pi r³

       M = rgo 4/3 π r³

give us the density 37800 kg / m³ and the radius of 5 cm

       M = 37800 4/3 π 0.05³

       M = 19.8 kg

a) asks us for the moment of inertia of the sphere with respect to its center of mass

        I = 2/5 M r²

        I = 2/5 19.8 0.05²

        I = 0.0198 kg m²

b) the moment of inertia with respect to the turning point, for this we will use the theorem of parallel axes

        I = I_cm + M d2

where d is the distance from the body to the point of interest

        I_cm = 0.0198 kg m²

the distance to the pivot point is

        l = length of the bar + radius of the sphere

        l = 1 + 0.05 = 1.005 m

        I = 0.0198 + 19.8 1.05²

        I = 21.85 kg m²

Answer:

a

 [tex]Q_e  =  -4.39 *10^{11}  \  C [/tex]

b

[tex]Q_p  =  + 2.395*10^{-8} \  C [/tex]

Explanation:

Generally the number of electron in the given mass is  mathematically evaluated as

        [tex]N_e =  \frac{2.5}{m_e }[/tex]

Here  m_e is the mass of electron with value [tex]m_e =  9.11 * 10^{-31} \  kg[/tex]

    =>  [tex]N_e =  \frac{2.5}{ 9.11 * 10^{-31} }[/tex]

       =>  [tex]N_e =2.74 *10^{30} \  electrons [/tex]

The total electric charge is mathematically represented as

       [tex]Q_e  =  N_e  *  e[/tex]

Here e is the charge on a single electron with value  [tex]e  =  1.60 *10^{-19}  \  C[/tex]

 So

          [tex]Q_e  =  -2.74 *10^{30}   *  1.60 *10^{-19} [/tex]

          [tex]Q_e  =  -4.39 *10^{11}  \  C [/tex]

The  negative sign is because we are considering electron

Generally the number of  protons in the given mass is  mathematically evaluated as

    [tex]N_p =  \frac{2.5}{m_p }[/tex]

Here  m_p is the mass of electron with value [tex]m_e =  1.67 * 10^{-27} \  kg[/tex]

    =>  [tex]N_p =  \frac{2.5}{ 1.67 * 10^{-27} }[/tex]

       =>  [tex]N_p =1.497 *10^{27} \  protons [/tex]

The total electric charge is mathematically represented as

       [tex]Q_p  = + N_p  *  e[/tex]

Here p is the charge on a single proton with value  [tex]p  =  1.60 *10^{-19}  \  C[/tex]

 So

          [tex]Q_p  =  +1.497 *10^{27}   *  1.60 *10^{-19} [/tex]

          [tex]Q_p  =  + 2.395*10^{-8} \  C [/tex]

Answer:

Hello!

Sorry you haven't put up an image of your question! Without it we can't answer your question!

Explanation:

Maybe put up another one and it'll be answered!

:D

Answer:

44 years

Explanation:

Use half life equation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

0.25 A₀ = A₀ (½)^(t / 22)

0.25 = (½)^(t / 22)

t / 22 = 2

t = 44

44 sec is half life of a given sample of radium is 22 years the sample will reduce to 25% of its original value.

The period of time it takes for one-half of a radioactive isotope to decay is known as the half-life. A given radioactive isotope's half-life is constant; it is unaffected by external factors and independent of the isotope's starting concentration.

Use half life equation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

0.25 A₀ = A₀ (½)^(t / 22)

0.25 = (½)^(t / 22)

t / 22 = 2

t = 44 sec

44 sec is half life of a given sample of radium is 22 years the sample will reduce to 25% of its original value.

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Answer:

i think gravity created a force strong enough to push him down.but it also depends how slow or fast the bus is going

Explanation:

gravity as we all now it is pretty strong so if the bus is going fast then the person standing up will fall but if the bus is going pretty slow then it'll just nudge him.

Answer:

im going between 2 of them b and c but i would have choose b

Responder:

Explicación:

Usaremos la ecuación de movimiento para determinar la altura de la bola medida desde la parte superior del edificio.

Usando la ecuación para obtener la altura de caída

S = ut + 1 / 2gt²

u es la velocidad inicial = 25 m / s

g es la aceleración debida a la gravedad = 9,81 m / s²

t es el tiempo = 7 segundos

S es la altura de la caída

S = 25 (7) +1/2 (9,81) × 7²

S = 175 + 4,905 (49)

S = 175 + 240,345

S = 415,35 m

Esto significa que la pelota se elevó a 415,35 m de altura

La altura vertical máxima alcanzada es de 31,88 m.

Tenemos la siguiente información de la pregunta;

Velocidad inicial = 25 m/s

Velocidad final = 0 m/s (a la altura máxima)

tiempo empleado = 3,5 minutos (el tiempo empleado para subir y bajar es igual).

Usando la ecuación;

v^2 = u^2 - 2gh

Dado que v = 0

u^2 = 2gh

h = tu^2/2g

h = (25)^2/2 *9.8

h = 31,88 m

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Answer:

The answer to your question is C

Explanation:

acceleration is a vector quantity because it has both magnitude and direction

The correct answer is A) d = v * t

Explanation:

When writing an equation the goal is to represent the equality between different mathematical expressions or elements. Due to this, in an equation the symbol = is always used. Additionally, to translate a sentence into an equation, the variables should be represented using numbers or letters.

For example, in the sentence "The distance traveled is the speed multiplied by the time" there are three variables mentioned: distance, speed, and time. Also, these can be represented through the letters d (distance), v (speed or velocity), and t (time). Besides this, the sentence explains speed should be multiplied by time, which means it should be written as v × t or v * t and this is equivalent (=) to distance or t. According to this, the final equation would be d = v * t.

Answer:

F=200N

a=500m/s2​

Mass=?

Explanation:

F=ma

200=m*500

200/500=m

Mass=0.4kg

Answer:

(a) , .  and .

(b)[tex]\vec A - \vec C=22 \hat i -10 \hat j[/tex].

(c)[tex]|\vec A - \vec B|=63.13[/tex] and the direction [tex]\theta =[/tex] 124.56°.

Explanation:

Given that,

,

and

[tex]\vec {C}=2 \hat i +43 \hat j[/tex]

(a) The magnitude of a vector is the square root of the sum of the square of all the components of the vector, i.e. for a ,.

So, the magnitude of the is

[tex]|\vec A|=\sqrt {24^2+ 33^2}[/tex]

[tex]\Rightarrow |\vec A|=\sqrt {1665}[/tex]

.

The magnitude of the is

[tex]|\vec B|=\sqrt {55^2+ (-12)^2}[/tex]

[tex]\Rightarrow |\vec B|=\sqrt {3169}[/tex]

.

And, the magnitude of the is

[tex]|\vec C|=\sqrt {2^2+ 43^2}[/tex]

[tex]\Rightarrow |\vec C|=\sqrt {1853}[/tex]

.

(b) The difference between the two vectors is the difference between the corresponding components of the vectors. So, the required expression of is

[tex]\vec A - \vec C=(24 \hat i +33 \hat j) - (2 \hat i +43 \hat j)[/tex]

[tex]\Rightarrow \vec A - \vec C=24 \hat i +33 \hat j - 2 \hat i -43 \hat j[/tex]

[tex]\Rightarrow \vec A - \vec C=22 \hat i -10 \hat j[/tex]

(c) The expression of is

[tex]\vec A - \vec N=(24 \hat i +33 \hat j) - (55 \hat i -12 \hat j)[/tex]

[tex]\Rightarrow \vec A - \vec B=24 \hat i +33 \hat j - 55\hat i +12 \hat j[/tex]

[tex]\Rightarrow \vec A - \vec B=-31 \hat i +45 \hat j\;\cdots (i)[/tex]

The magnitude of is

[tex]|\vec A - \vec B|=\sqrt {(-31)^2+55^2}[/tex]

[tex]\Rightarrow |\vec A - \vec B|=\sqrt {3986}[/tex]

[tex]\Rightarrow |\vec A - \vec B|=63.13[/tex]

Now, if a vector [tex]\vec V= -\alpha \hat i +\beta \hat j[/tex] in 3rd quadrant having direction [tex]\theta[/tex] with respect to [tex]\hat i[/tex] direction, than

in the anti-clockwise direction.

Here, from equation (i), for the vector [tex]\vec A - \vec C[/tex], [tex]\alpha=31[/tex] and [tex]\beta=45[/tex].

[tex]\Rightarrow \theta = \pi-\tan ^{-1}\left(\frac {45}{31}\right)[/tex]

180°-55.44° [as \pi radian= 180°]

124.56° in the anti-clockwise direction.

(d) Vector diagrams for [tex]\vec A +\vec B[/tex] and [tex]\vec A - \vec B[/tex] has been shown  

in the figure(b) and figure(c) recpectively.

Vector [tex]\vec A - \vec B[/tex] is in 3rd quadrant as calculated in part (c).

While Vector [tex]\vec A +\vec B=(24 \hat i +33 \hat j)+(55 \hat i -12 \hat j)[/tex]

[tex]\Rightarrow \vec A +\vec B=79 \hat i +21 \hat j[/tex], which is in 1st quadrant as both the components are position has been shown in figure(b).

Answer:

The critical radius of the plastic insulation is 0.72 inches.

Explanation:

Given that,

Diameter = 0.091 in

Thickness = 0.02 in

Initial temperature = 90°F

Final temperature = 50°F

Heat transfer coefficient = 2.5 Btu/h.ft²°F

Material conductivity = 0.075 Btu/h.ft °F

We need to calculate the critical radius of the plastic insulation

Using formula of critical radius

[tex]r_{cr}=\dfrac{2K}{h}[/tex]

Where, k = Material conductivity

h = Heat transfer coefficient

Put the value into the formula

[tex]r_{cr}=\dfrac{2\times0.075}{2.5}[/tex]

[tex]r_{cr}=0.06\ ft[/tex]

[tex]r_{cr}=0.72\ inches[/tex]

Hence, The critical radius of the plastic insulation is 0.72 inches.

Answer:

t=8

Explanation:

u have solution I give solution also

don't mark plzz follow y

Answer:

C. Muddy Water

"Ampere" means 1 coulomb of charge every second.

12A means 12 coulombs of charge every second.

5.2 minutes = (5.2) x (60 seconds) = 312 seconds

12A for 312 seconds means (12) x (312)  = 3,744 coulombs of charge

1 coulomb is the amount of charge carried by 6.24 x 10¹⁸ electrons .

So 12A for 312 seconds means (3,744) x (6.24 x 10¹⁸) electrons.

That's  2.336 x 10²² electrons .

or  23,360,000,000,000,000,000,000 electrons .

(rounded to the nearest 10 quintillion).