PLEASEHELP THANK YOU SM

I probably don't have to tell you that the other answer is nonsense, but I'll do it all the same, just in case... Half-life is defined as the time it takes for some radioactive substance to decay to half its original amount.

If it takes n half-lives for some substance with a starting amount of A to decay to a final amount of B, then

[tex]B = \dfrac{A}{2^n}[/tex]

1. If the half-life is x, then after 1 half-life, 5000 units of this substance decays to 2500 units. After another half-life, this decays to 1250. After another, this in turn decays to 625.

So 3 half-lives are required.

In terms of the equation above, we solve for n such that

[tex]625 = \dfrac{5000}{2^n} \implies 2^n = 8 \implies n=3[/tex]

since 2³ = 8.

2. Count how many times you halve 15,000 to end up with 3750:

15,000/2 = 7500

7500/2 = 3750

===>   2 half-lives

In other words,

[tex]3750 = \dfrac{15,000}{2^n} \implies 2^n = 4 \implies n=2[/tex]

3. After 1 half-life, you would end up with

12,000/2 = 6000

and after another half-life,

6000/2 = 3000

i.e.

[tex]\dfrac{12,000}{2^2} = \dfrac{12,000}4 = 3000[/tex]

4. After 1 half-life, you have

26,000/2 = 13,000

After 2 half-lives,

13,000/2 = 6500

After 3 half-lives,

6500/2 = 3250

After 4 half-lives,

3250/2 = 1625

i.e.

[tex]\dfrac{26,000}{2^4} = \dfrac{26,000}{16} = 1625[/tex]

5. If the half-life is 3 years, then 15 years = 3 half-lives.

In the last 3 years, 20,000 would have decayed to 10,000.

In the second-to-last 3 years, 40,000 would have decayed to 20,000.

In the first 3 years, 80,000 would have decayed to 40,000.

i.e.

[tex]\dfrac{x}{2^3} = 10,000 \implies x = 8\times10,000 = 80,000[/tex]

Answer:

Explanation:

Let the equilibrium position of third charge be x distance from q₁.

Force on third charge due to q₁

= 9 x 10⁹ x 5 x 10⁻⁹ x 15 x 10⁺⁹ / x²

Force on third charge due to q₂

= 9 x 10⁹ x 2 x 10⁻⁹ x 15 x 10⁺⁹ /( .40-x)²

Both the force will act in opposite direction and for balancing , they should be equal.

9 x 10⁹ x 5 x 10⁻⁹ x 15 x 10⁺⁹ / x² = 9 x 10⁹ x 2 x 10⁻⁹ x 15 x 10⁺⁹ /( .40-x)²

5  / x² = 2 / ( .4 - x )²

Taking square root on both sides

2.236 / x = 1.414 / .4 - x

2.236 ( .4 - x ) = 1.414 x

.8944 - 2.236 x = 1.414 x

.8944 = 3.65 x

x = .245 m

24.5 cm

So the third charge should be at a distance of 24.5 cm from q₁ .

Answer:

θ = 17.67°

Explanation:

The grating equation can be used here to find the angle. The grating equation is given as follows:

[tex]m\lambda = dSin\ \theta[/tex]

where,

m = order = 2

d = 3.88 x 10⁻⁶ m

λ = wavelength of light = 589 nm = 5.89 x 10⁻⁷ m

θ = angle = ?

Therefore, using these values in the equation, we get:

[tex](2)(5.89\ x\ 10^{-7}\ m) = (3.88\ x\ 10^{-6}\ m)Sin\theta \\Sin\theta = \frac{(2)(5.89\ x\ 10^{-7}\ m)}{(3.88\ x\ 10^{-6}\ m)}\\\\\theta = Sin^{-1}(0.3036)[/tex]

θ = 17.67°

Answer:17.67

Explanation:

Answer:

True

Explanation:

There basically four type of forces in nature that govern the entire laws of nature. These four forces are

1.Gravity.  

2.The weak force.  

3.Electromagnetism.  

4.The strong force.

The weak force as it is called is the weakest of the all the forces mentioned above. It is also called weak nuclear interaction force and is responsible for particle decay.

Answer:

I think the answer is option B

Complete Question:

A tungsten wire is 1.5 m long and has a diameter of 1.0 mm. A current of 60 mA flows through the wire. The resistivity of the wire is 5.6 * 10^-8 Ωm. What is the potential difference across the ends of the wire?

Answer:

Potential difference, V = 0.00642 Volts.

Explanation:

Given the following data;

Diameter = 1 mm to meters = 1/1000 = 0.001 m

Length = 1.5m

Current = 60mA = 60/1000 = 0.06 Amperes.

Resistivity = 5.6 * 10^-8 Ωm

To find the potential difference across the ends of the wire;

First of all, we would determine the cross-sectional area of the wire (circle);

[tex] Radius, r = \frac {diameter}{2} [/tex]

[tex] Radius = \frac {0.001}{2} [/tex]

Radius = 0.0005 m

Area of wire (circle) = πr²

Substituting into the above formula, we have;

Area  = 3.142 × (0.0005)²

Area = 3.142 × 2.5 × 10^-7

Area = 7.855 × 10^-7 m²

Next, we find the resistance of wire;

Mathematically, resistance is given by the formula;

[tex] Resistance = P \frac {L}{A} [/tex]

Where;

P is the resistivity of the material.

L is the length of the material.

A is the cross-sectional area of the material.

Substituting into the formula, we have;

[tex] Resistance = 5.6 * 10^{-8} \frac {1.5}{7.855 * 10^{-7}} [/tex]

[tex] Resistance = 5.6 * 10^{-8} * 1909611.712 [/tex]

Resistance = 0.107 Ohms.

Now, we can find the potential difference using the formula;

[tex] V = IR[/tex]

Where;

V represents voltage or potential difference measured in volts.

I represents current measured in amperes.

R represents resistance measured in ohms.

Substituting into the formula, we have;

[tex] V = 0.06*0.107[/tex]

Potential difference, V = 0.00642 Volts.

Answer:

Rows are called periods, columns are called groups or families, and elements in the same group have the same number of valence electrons and often show similar properties and reactivity.  

Explanation:

Answer:

Explanation:

The sun sends out solar wind constantly - charged particles that can degrade visual sensors and the skin of spacecraft, and the occasional blast of a solar flare, which can send out clouds of charged ions that can disrupt communications and electronics on board probes and satellites.

Hope this Helps <3

Answer:

Explanation:

The force of 80N is applied on sled at 53⁰

Its horizontal  component = 80cos53

= 48.14 N .

Its horizontal component will pull forward the sled and friction will prevent its forward motion . As sled is moving with constant velocity , net force on it is zero .

Hence forward push = frictional force

Frictional force = 48.14 N.

Answer:

It is easy to imagine representing a narrow beam of light by a collection of parallel arrows—a bundle of rays. As the beam of light moves from one medium to another, reflects off surfaces, disperses, or comes to a focus, the bundle of rays traces the beam's progress in a simple geometrical manner.

I hope it's helpful!

Answer:It is easy to imagine representing a narrow beam of light by a collection of parallel arrows—a bundle of rays. As the beam of light moves from one medium to another, reflects off surfaces, disperses, or comes to a focus, the bundle of rays traces the beam's progress in a simple geometrical manner.

Explanation:

Answer: An electric circuit includes a device that gives energy to the charged particles constituting the current, such as a battery or a generator; devices that use current, such as lamps, electric motors, or computers; and the connecting wires or transmission lines.

Explanation: Hope this helped! <3

Answer:

9.0, might be to late but someone in the future might need it.

Answer:

C.     9.0

Explanation:

I like boys

Answer:

I am not sure really.

Explanation:

I just don't know

Answer:

Physical change

Explanation:

its changing matter but is still water so its not chemicly changing

What help do you want? If you tell, I may help you.

Answer:

450 kgm/s upward

Explanation:

From the question,

Change in monentum = mass× change in velocity

ΔM = mΔv....................... Equation 1

ΔM = m(v-u).................. Equation 2

Where ΔM = Change in momentum, m = mass of the gymnast, v = final velocity, u = initial velocity

Given: m = 50 kg, v = -4 m/s. u = 5 m/s

Substitute these values into equation 2

ΔM = 50(-4-5)

ΔM = 50(-9)

ΔM = -450 kgm/s

Hence the change in momentum of the gymnast is 450 kgm/s upward

Answer:

The width of the intersection is 20 meters

Explanation:

The speed with which the cyclist is riding, v₁ = 6.20 m/s

The rate at which the car starts to accelerate, a = 3.844 m/s²

The initial velocity of the car = The car is stationary at the start = 0 m/s

The time at which the cyclist and the car reach the other side of the intersection = The same time;

Let 't' represent the time at which the cyclist and the car both reach the other side of the intersection, we have;

The distance travelled by the cyclist = The distance traveled by the car

∴ v₁ × t = 1/2 × a × t²

Plugging in the values for 'v₁', and 'a' in the above equation, we get;

6.20 × t = 1/2 × 3.844 × t²

∴ 1.922·t² - 6.20·t = 0

∴ t·(1.922·t - 6.20) = 0

t = 0, or t = 6.20/1.922 = 100/31

The time at which the cyclist and the car both reach the other side of the intersection, t = 100/31 seconds

The with of the intersection, w = v₁ × t

∴ w = 6.20 × 100/31 = 100/5 = 20

The width of the intersection, w = 20 meters.

Answer:

hello your question is vague hence I will provide a general answer about what was known about atoms in the 19th Century

answer :

By the end of the 19th century more than half of the population believed in the presence of atoms and also in the 19th Century is was a known fact that atoms determine the chemical properties of an element

Explanation:

By the end of the 19th century more than half of the population believed in the presence of atoms and also by the 19th Century is was a known fact that atoms determine the chemical properties of an element.

John Dalton reintroduced the presence of atoms in 1800 with evidence which he used to develop atomic theory. with this theory people believed in the presence of atoms in nature and also that atoms determine the chemical properties of an element .

Answer:

Since light does not actually pass through this point, the image is referred to as a virtual image. Observe that when the object in located in front of the focal point of the converging lens, its image is an upright and enlarged image that is located on the object's side of the lens.

Explanation:

Answer:

Magma is less dense than the surrounding rock which causes it to rise. When magma reaches the surface it is then called lava and the eruptions of lava and ash produce volcanoes. The lava that reaches the Earth's surface will harden and become igneous rock.

Answer:

c

Explanation:

every other option is a conductor

Answer:

An electric current into a magnetic field

Explanation:

:) please give a heart if this helped you in any way. ;O)

I think the answer for the following question is A.

Answer:

B

Explanation:

because it has more power

The Model A represents a neutral atom. hence option A is correct.

Atom is smallest entity of a body. Body is made up of atoms. it is basic building block of a body. An atom consist of electrons, protons and neutrons as sub atomic particle. whole mass of the atom is concentrated at the center of the atom which we call it as nucleus, nucleus consist of proton and neutron. Electron revolve around the nucleus at determined(fixed) orbit. Total number of protons in the atom decides the atomic number and the elements in the periodic table. The electrons which are completely filled orbitals are called as core shell electrons and which are not filled completely are called as valence electron. valence electrons are responsible for physical and chemical properties of the element. Elements which are on same column in periodic table have same number of valence electrons . Hence they have same properties.

Atomic number of Nitrogen is 7. Hence neutral atom of nitrogen has 7 electrons in his orbits.

Hence option A is correct.

To know more about Atom :

https://brainly.com/question/30898688

#SPJ5.

Answer:

b.

Explanation:

due to the higher mass of the 25 kg body as compared to the 5kg body ,a smaller velocity will catch up quickly with the 5kg object, but a slight increase in its velocity will have a much higher momentum

Answer:

degree

liquid

mass-volume

Explanation: