What is the name for family labeled #4 (Yellow)?
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Alkaline Earth Metals
Metalloids
Transition Metals
Alkali Metals

Answer:

222/88 Ra

Explanation:

We have to wait 5.57 half lives for a radioactive sample to drop to 2.10 % of its original activity.

To find the tike taken for the activity, we need to know about radioactivity and half-life.

                R=R₀e^(-λ×t)

                 t= 1/λ ln(R₀/R)

    t=(half-life/ln2)×ln(R₀/R)

Here R=0.021R₀, so t= (half-life/ln2)×ln(R₀/0.021R₀)=5.57 half-lives

Thus, we can conclude that we have to wait 5.57 half lives for a radioactive sample to drop to 2.10 % of its original activity.

Learn more about radioactivity here:

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Answer:

a

Explanation:

Answer:

C

Explanation:

Sled A has more potential energy because it's mass is 100 kg, and it is higher up than Sled B. The more high up the sled is and the lighter it is, the faster it gets, it creates more and more potential energy.

Hope this helps!

Answer:

Object's weight = 6,839.42 N

Explanation:

Given

Above waterline = 30%

Volume of object = 1m^3

Required

Determine the weight of the object

First, we need to calculate its Mass

Mass = Density of Water * Volume of object in water

Density of water = 997kg/m³

If 30% is above waterline, then 70% is in water.

So:

Mass = Density of Water * Volume of object in water

Mass = 997kg/m³ * 70%m³

Mass = 997kg * 70%

Mass = 697.9 kg

The object weight sis then calculated as thus:

Weight = Mass * Acceleration of gravity

Weight = 697.9 kg * 9.8m/s²

Weight = 6 839.42 N

Answer:

a). a = F/m

Explanation:

Formula is F=ma

Answer:

Explanation:

Step one:

given data

period T= 4seconds

velocity v= 7m/s

wave lenght λ=?

Step two:

we know that f=1/T

the expression relating period and wave lenght is

v=λ/T

λ=v*T

λ=7*4

λ=28m

The wavelength of the wave is 28m

Answer:

in a spontaneous process, the entropy of the universe increases.

Explanation:

Entropy is a measure of of the degree of  randomness or disorderliness in a system.

The second law of thermodynamics can be stated as follows; "in any spontaneous process, the entropy of the universe increases."  

The universe here refers to the system's disorder and the disorder of the surroundings.  Therefore, a spontaneous process can occur, in which the entropy of the system decreases, only if the entropy increases in the surroundings.

For instance, when ice freezes, the entropy of liquid water decreases, that is, the entropy of the system decreases. However, heat is given off to the surroundings and the entropy of the surroundings increases. This is an obvious expression of this law.

Answer:

pt 1: [tex]m=1.66698*10^{21} kg[/tex]

Pt 2: [tex]KE=1212.23531 J[/tex]

Explanation:

Information Given: (p = density)

l = 5200km  d = 35km p = 2700kg/[tex]m^{2}[/tex]

Part 1: Mass

Part 2: Kinetic Energy

[tex]KE=\frac{1}{2}mv^2[/tex]

[tex]KE=\frac{1}{2} (1.66698*10^{21})(1.20497*10^{-9})^2[/tex]

[tex]KE=1212.23531 J[/tex]

Part 3: Jogger Speed

set up, because I don't have the mass :(

Information given:

[tex]KE_{jogger}[/tex]

Hope it helps :)

Answer: b is probly correct  beacuse all the others make no sence

The statement that is true about international space station is The force of gravity produces the same acceleration for the earth and the space station.

International space station is a space station that is located at the lower part of the Earth's orbit . It is the third largest space object in the space and it is a multinational project that involves five different space agencies are NASA, Roscosmos, JAXA, ESA, and CSA.

Therefore, The statement that is true about international space station is The force of gravity produces the same acceleration for the earth and the space station.

Learn more about international space station below.

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Answer:

D. The airplane will turn towards the east

Explanation:

If the airplane is thrown straight towards the north, the window which is moving from left (west) to right (east) the wind will knock the plane towards the right (east) since thats the way it is blowing.

Answer:

The fundamental frequency is  [tex]f_1 =128 \ Hz[/tex]

Explanation:

From the question we are told that

   The frequency of one harmonics is  [tex]f_x= 448 \ Hz[/tex]

    The next higher harmonic is  [tex]f_z = 576 \ Hz[/tex]

Generally the frequency of an air column open at both ends is mathematically represented as

              [tex]f_n = \frac{nv }{ 2 L }[/tex]

Here n  is the order of the harmonics (frequency)

        v is the velocity of the sound

        L  is the length of the column

So for one harmonics we have that

        [tex]f_k = \frac{n v }{2L}[/tex]

Then for the next higher harmonics

       [tex]f_x = \frac{n+1 ) v}{2 L }[/tex]

Generally the difference between these frequencies is mathematically represented as  

       [tex]f_z- f_x = \frac{(n+1 )v}{ 2L} - \frac{(n )v}{ 2L}[/tex]

=>    [tex]576 - 448 = \frac{vn + v - nv }{2L}[/tex]

=>    [tex]\frac{ v }{2L} = 128[/tex]

Generally for fundamental  frequency n =  1

So  

       [tex]f_1 = n * \frac{v}{2L}[/tex]

So

       [tex]f_1 =1 * 128[/tex]

=>    [tex]f_1 =128 \ Hz[/tex]

Black I think

this is due to the fact that blue lights only reflect blue things so if yellow is shone on it it will reflect black appearance.

how it useful

Answer:

F = 2250 [N]

Explanation:

In order to solve this problem, we must first use the following equation of kinematics.

[tex]v_{f}^{2} =v_{o}^{2}-2*a*x[/tex]

where:

Vf = final velocity = 0 (come to rest)

Vo =  initial velocity = 30 [m/s]

a = acceleration or desaceleration [m/s²]

x = distance = 100 [m]

[tex](0)=30^{2} -2*a*100\\900 = 200*a\\a = 4.5 [m/s^{2}][/tex]

Now we must use the following equation of kinetics, which is based on Newton's second law that explains that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = force [N]

m = mass = 500 [kg]

a = acceleration = 4.5 [m/s²]

[tex]F = 500*4.5\\F = 2250 [N][/tex]

Answer:

The value is  [tex]|\vec B| = 1.267 *0^{-8} \ T[/tex]

Explanation:

From the question we are told that  

   The magnitude of the electric fields is  [tex]E = 3.80 V/m[/tex]

Generally speed of light is mathematically represented as

        [tex]c = \frac{|\vec E|}{ |\vec B|}[/tex]

Here c is the speed of light with value  [tex]c = 3.0*10^{8} \ m/s[/tex]

        [tex]|\vec B |[/tex]  is the  magnitude of the magnetic field so  

=>         [tex]|\vec B| = \frac{|\vec E|}{c}[/tex]

=>         [tex]|\vec B| = \frac{ 3.80 }{3.0*10^{8}}[/tex]

=>         [tex]|\vec B| = 1.267 *0^{-8} \ T[/tex]

Answer:

a

  [tex]\theta _1 =0.687 ^o[/tex]

  [tex]\theta _2 =0.630 ^o[/tex]

b

 Generally given that the domain arcsine function is  between -1 and 1 then the arcsine of 2.22 will not be valid

Generally given that the domain arcsine function is  between -1 and 1 then the arcsine of 2.1 will not be valid

Explanation:

From the question we are told that

     The slit grating is  [tex]N = 68 \ slits / cm = 6800 \ slits / m[/tex]

      The order of spectrum is [tex]n = 4[/tex]

Generally the width of the slit is mathematically represented as  

               [tex]a = \frac{1}{ 6800}[/tex]      

=>            [tex]a = 0.000147 \ m[/tex]  

Generally the condition for constructive interference is

              [tex]asin\theta = n * \lambda[/tex]

Now for the first wavelength the angle is evaluated as

             [tex]\theta _1 = sin ^{-1} [ \frac{n \lambda_1 }{a} ][/tex]

    =>     [tex]\theta _1 = sin ^{-1} [ \frac{4* 434 *10^{-9} }{ 0.000147 } ][/tex]

    =>    [tex]\theta _1 =0.687 ^o[/tex]

Now for the second wavelength the angle is evaluated as

             [tex]\theta _2 = sin ^{-1} [ \frac{n \lambda_2 }{a} ][/tex]

    =>     [tex]\theta _2 = sin ^{-1} [ \frac{4* 410 *10^{-9} }{ 0.000147 } ][/tex]

    =>    [tex]\theta _2 =0.630 ^o[/tex]

Gnerally if grating is   [tex]N = 12800 \ slits per cm = 1280000 \ slits / m[/tex]

Generally the width of the slit is mathematically represented as  

               [tex]a = \frac{1}{ 1280000}[/tex]      

=>            [tex]a = 7.813 *10^{-7} \ m[/tex]  

Generally the condition for constructive interference is

              [tex]asin\theta = n * \lambda[/tex]

Now for the first wavelength the angle is evaluated as

             [tex]\theta _1 = sin ^{-1} [ \frac{n \lambda_1 }{a} ][/tex]

            [tex]\theta _1 = sin ^{-1} [ \frac{4* 434 *10^{-9} }{ 7.813*10^{-7} } ][/tex]

    =>     [tex]\theta _1 = sin ^{-1} [ 2.22][/tex]

Generally given that the domain arcsine function is  between -1 and 1 then the arcsine of 2.22 will not be valid

    =>    [tex]\theta _1 =0.687 ^o[/tex]

Now for the second wavelength the angle is evaluated as

             [tex]\theta _2 = sin ^{-1} [ \frac{n \lambda_2 }{a} ][/tex]

    =>     [tex]\theta _2 = sin ^{-1} [ \frac{4* 410 *10^{-9} }{ 7.813*10^{-7} } ][/tex]

     =>  [tex]\theta _2 = sin ^{-1} [2.1 ][/tex]

Generally given that the domain arcsine function is  between -1 and 1 then the arcsine of 2.22 will not be valid

Answer:

Explanation:

Step one:

given data

speed = 123m/s

radius of circle= 4330m

Step two:

We need to find the circumference of the circle, it represents the distance traveled

C=2πr

C= 2*3.142*4330

C= 27209.72m

Step three:

We know that velocity= distance/time

time= distance/velocity

time= 27209.72/123

time=221.2 seconds

in minute = 221.2/60

time= 3.7 min

Answer: Plates shifting

Explanation: After years and years of plates colliding into solid rock, they slowly become closer together. As recent studies have shown, Africa is currently moving closer to Europe one centimeter every year (one inch every 2.5 years).

Answer:

nvudbwasivnjlscv bwbfvsz

Explanation:

Answer:no

Explanation:

No.....................................

Answer:

Centripetal acceleration = 83.77m/s²

Explanation:

Given the following data;

Radius, r = 0.13m

Velocity, v = 3.3m/s

To find centripetal acceleration;

Centripetal acceleration is given by the formula;

[tex] Acceleration, a = \frac {v^{2}}{r}[/tex]

Substituting into the equation, we have;

[tex] Centripetal \; acceleration, a = \frac {3.3^{2}}{0.13}[/tex]

[tex] Centripetal \; acceleration, a = \frac {10.89}{0.13}[/tex]

Centripetal acceleration = 83.77m/s²

Therefore, the centripetal acceleration of the edge of the disc is 83.77 m/s².

Answer:

the answer is 84

Explanation:

Answer:

955 J  

Explanation:

PV = nRT

500 x 10³ x 1.8 x 10⁻³ = nRT

= 900 J

work done by gas in isothermal expansion

= nRT lnV₂ / V₁

= 900 ln 5.2 / 1.8

= 900 x ln 2.89

= 900 x 1.06

= 955 J  

Answer:

That is false. Take a look at this way. You can push a ball with your own breath, you just need to blow it. And you can pull something from afar with a magnet. It is possible to do both.

Explanation:

Not all physical things can be done only physically. Like I just said, it is possible to use other forces (no, not the dark side one),  such as a magnetic force, displayed by a magnet or anything with a force like so.

Answer:

Explanation:

The potential energy of a body can be found by using the formula

PE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 10 m/s²

From the question we have

PE = 30 × 10 × 15

We have the final answer as

Hope this helps you

Answer:

It is called an ion.

Explanation:

Atoms of elements can lose or gain electrons making them no longer neutral, they become charged. A charged atom is called an ion. When an atom loses electron(s) it will lose some of its negative charge and so becomes positively charged. A positive ion is formed where an atom has more protons than electrons.

Answer:

About 1000 miles.

Explanation:

Answer:

d = 0.05 [m] = 50 [mm]

Explanation:

We must remember the principle of conservation of energy which tells us that energy is transformed from one way to another. For this case, the initial kinetic energy is transformed into useful work that is equal to the product of force by distance.

[tex]E_{k}=F*d\\400 = 8000*d\\d = 0.05 [m] = 50 [mm][/tex]

Answer:

A. ) F₁ₓ = -45.0 N F₁y = 53.6 N

B.)  F₂ₓ = 3.48 N F₂y = -19.7 N

C.)  Fₓ = -41.5 N Fy = 33.9 N

D)  F = 53.6 N

E)  θ = -39. 2º (320.8º)

Explanation:

A)

       [tex]F_{x1} = F_{1} * cos (130) = 70 N * cos (130) = -45 N (1)\\F_{y1} = F_{1} * sin (130) = 70 N * sin (130) = 53.6 N (2)[/tex]

B)

       [tex]F_{x2} = F_{2} * cos (280) = 20 N * cos (280) = 3.48 N (3)\\F_{y2} = F_{2} * sin (280) = 20 N * sin (280) = -19.7 N (4)[/tex]

C)  

        sum of the x- and - y components of F₁ and F₂:

D)

       [tex]F_{t} =\sqrt{F_{x} ^{2} + F_{y} ^{2} } = \sqrt{(-41.5N)^{2} +(33.9N)^{2}} = 53.6 N (7)[/tex]

E)

       [tex]\theta = arc tg \frac{33.9N}{(-41.5N)} = arc tg (-0.817) = -39. 2 \deg[/tex]

Complete Question

What is the minimum angular velocity (in rpm) for swinging a bucket of water in a vertical circle without spilling any? The distance from the handle to the bottom of the bucket is 35 cm. The student has 70-cm-long arms

Answer:

The value is  [tex]w__{rpm} } = 29.17 \ rpm[/tex]

Explanation:

From the question we are told

    The distance from the handle to the bottom of the bucket is  [tex]d = 35 \ cm = 0.35 \ m[/tex]

      The length of the students arm is  L = 70 cm  = 0.70  m

   Generally the acceleration due to gravity experienced by the bucket of  water is mathematically represented as

       [tex]g = w^2 * r[/tex]

Here is is the radius of the circle which swinging of the bucket makes and this is mathematically represented as

       [tex]r = L + d[/tex]

So

         [tex]g = w^2 * ( L + d )[/tex]

= >     [tex]w = \sqrt{\frac{g }{ L + d } }[/tex]

= >     [tex]w = \sqrt{\frac{ 9.8}{ 0.7 + 0.35} }[/tex]

= >     [tex]w = 3.055 \ rad/s[/tex]

Generally the angular speed in revolution per minute is mathematically represented as

        [tex]w__{rpm} } = \frac{w * 60 }{2 \pi }[/tex]

=>      [tex]w__{rpm} } = \frac{3.055 * 60 }{2 * 3.142 }[/tex]

=>      [tex]w__{rpm} } = 29.17 \ rpm[/tex]