Ray bought 15 pencils for $7.75 each, some cost $45 each , the rest cost $65. how many of each did ray buy?

The time it takes for the current to reach 63% of its final value in a circuit with a solenoid/inductor is determined by the values of L and R in the circuit.

I(t) = I0 (1 -\(e^(-t/τ))\)

where I0 is the initial current, t is the time, and τ is the time constant of the circuit, given by:

τ = L/R

where L is the inductance of the solenoid/inductor and R is the resistance of the circuit.

At 63% of the final value, the current is given by:

0.63 I0

Setting this equal to the equation for I(t) and solving for t, we get:

t = τ ln(1/(1-0.63))

Substituting in the expression for τ and simplifying, we get:

t = L/(R ln(1/0.37))

A solenoid is a type of electromagnet that consists of a coil of wire wrapped around a ferromagnetic core. When an electric current flows through the coil, it generates a magnetic field that can attract or repel magnetic materials.

The strength of the magnetic field generated by a solenoid depends on several factors, including the number of turns in the coil, the current flowing through the coil, and the length and cross-sectional area of the core. Solenoids are used in a wide range of applications, including electrical switches, relays, and valves. They are also used in motors and generators to convert electrical energy into mechanical energy.

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When we view our galaxy from edge on, we get to see that our galaxy is bend towards earth.

A spiral galaxy typically has a rotating disc with spiral 'arms' that curve out from a dense central region. The Milky Way is a spiral galaxy. Four classes are used to classify galaxies: spiral; barred spiral; elliptical and irregular. The Milky Way is a large barred spiral galaxy. All the stars we see in the night sky are in our own Milky Way Galaxy. Our galaxy is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area. Generally, the dust and whirling arms of spiral galaxies such as the Milky Way look flat when seen edge-on, because they are oriented differently toward Earth.

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A force of 15 Newton stretches a spring to a total length of 30 cm and an additional force of 10 Newton's stretches to a Spring of 5 cm, the natural length of the spring is 58.5 cm

To find the natural length of the spring, we can use Hooke's law, which states that the force applied to a spring is directly proportional to the displacement of the spring from its natural length.

Let's denote the natural length of the spring as L.

According to the problem, a force of 15 Newton stretches the spring to a total length of 30 cm. This means that the displacement of the spring is 30 cm - L.

Using Hooke's law, we can set up the following equation:

Force = k * Displacement

where k is the spring constant.

For the first scenario, we have:
15 N = k * (30 cm - L)

Next, we are given that an additional force of 10 Newton's stretches the spring to a length of 5 cm. This implies that the displacement of the spring is 5 cm - L.

Using Hooke's law again, we can set up the following equation:

10 N = k * (5 cm - L)

Now we have two equations:

15 N = k * (30 cm - L)
10 N = k * (5 cm - L)

We can solve this system of equations to find the value of L, the natural length of the spring.

By dividing the second equation by 10, we get:

1 N = k * (0.5 cm - 0.1L)

Rearranging the equation, we have:

1 N = 0.5 k - 0.1kL

Now, let's substitute the value of k from the first equation into this equation:

1 N = 0.5 (15 N / (30 cm - L)) - 0.1 (15 N / (30 cm - L)) * L

Simplifying the equation, we get:

1 = 0.75 / (30 cm - L) - 1.5L / (30 cm - L)

Combining the terms on the right side of the equation, we have:

1 = (0.75 - 1.5L) / (30 cm - L)

Cross-multiplying, we get:

30 cm - L = 0.75 - 1.5L

Simplifying the equation, we have:

L - 1.5L = 0.75 - 30 cm

Combining like terms, we get:

-0.5L = -29.25 cm

Dividing both sides of the equation by -0.5, we get:

L = 58.5 cm

Therefore, the natural length of the spring is 58.5 cm.

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Answer:

0.0217 m

Explanation:

Ftom the question,

Applying Coulomb's law

F = kqq'/r²............... Equation 1

Where F = Electric Force, q and q' = First and second charge respectively, r = distance between the charges, k = coulomb's constant.

make r the subeject of the equation

r = √[(kqq')/F]............. Equation 2

Given: q = +3.6×10⁻⁸ C, q' = -3.2×10⁻⁸ C, F = -2.2×10⁻² N

Constant: k = 8.98×10⁹ Nm²/C²

Substitute these values into equation

r = √(+3.6×10⁻⁸×-3.2×10⁻⁸×8.98×10⁹/-2.2×10⁻²)

r = √(-103.4489×10⁻⁷/-2.2×10⁻²)

r = √(47.02×10⁻⁵)

r = 21.68×10⁻³

r ≈ 21.7×10⁻³ m.

r ≈ 0.0217 m

Hence the seperation between the two balloons is 0.0217 m

Answer:

1000 units for breakeven

Explanation:

Let x be the number of units sold at breakeven.

The total sales at the point would be $2x.

Variable costs would be $1x and fixed costs are $1000.

Total costs are = $1x + $1000

At breakeven: Sales = Costs

Sales =m Costs

$2x = $1x + $1000

$1x = $1000

x = 1000 units.

At 1000 units the sales are equal to the costs ("breakeven").

Answer: -110N

Explanation:

Assign a variable x to the unknown force. The net force was given as +25N, which means the sum of the two forces must equal +25N.

Subtract 135N on both sides

135 + x = 25

x = -110N

The negative sign indicates direction because force is a vector.

Answer:

125

Explanation:

use the formula e=1/2mv² and use m=10 and v=5

this produces the equation e=1/2x10x25=125

dont forget the units (J) ;)

Answer:

125J

Explanation:

K.e=1/2mv^2

=1/2(10)(5)^2

=125J

The base unit of length in the international system of units is the: meter (m)

The meter, ( symbol: m ) is the SI unit of length. It is derived by taking the fixed numerical value of the speed of light in vacuum c to be 299 792 458 when expressed in the unit m s-1

The SI base units are the standard units of measurement defined which is defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of quantities:

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Newton's second law and graphical analysis allow to find the results for the questions about the air resistance force are:

   A) The air resistance is proportional to the velocity because the graph of force vs velocity is linear.

   B) In the adjoint we see the free body diagram on the man, where all the forces are in equilibrium.

   C) The block acceleration is: a = - 0.03 m/s²

Part A

Newton's second law establishes a relationship between the net force and the product of the mass and the acceleration of the body

      ∑ F = m a

Where the bold letters indicate vectors, F is the forces, m the mass and the acceleration of the body.

Indicates that the only significant force is air resistance.

      ∑ F = \(f_{air\ resistence}\)

They give a table of force versus speed.

  F (N)    v (m / s)

 0.05       20

 1.25        40  

 2.51        60

 3.73        80

In the attachment we make a graph of the force versus velocity and we see that it is a linear relationship, therefore the air resistance must be proportional to the value of the body, an expression can be:

     f_{air\ resistence} = - b v

The results of the equation of the linear regression is:

     f = 0.0615 v -1.19

For this case the term b found from the linear regression is

     b = 0.0615 N s / m

Part 2

in the second attachment see a free body diagram of the force on the person

The normal force and weight are in balance.

The force applied by the person on the box (F) and there is a force applied by the box on the person (F '), are in equilibrium since the speed is constant, therefore the acceleration is zero.

Part 3

Indicate that the person stops, ask the acceleration of the block of mass 10 kg for the speed of 5 m / s.

Let's write Newton's second law for the x-axis.

           f_{air\ resistence} = m a

           - b v = m a

           a = \(- \frac{b v}{m}\)

Let's calculate

             a = \(- \frac{0.0615 \ 5}{10}\)  

             a = -0.03 m / a²

The negative sign indicates that the block is stopping.

In conclusion, using Newton's second law and graphical analysis we can find the results for the questions about the air resistance force are:

   A) The air resistance is proportional to the velocity because the graph of force vs velocity is linear.

   B) In the adjoint we see the free body diagram on the man, where all the forces are in equilibrium.

   C) The block acceleration is: a = - 0.03 m / s²

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i need the same question

Answer:

the one that has more negative sights so the first hand on your right :)

Answer:

b

Explanation:

The production function will have constant returns to scale if 2αβ = 1

Constant returns to scale (CRS) implies that if all inputs increase by a factor of λ, the output increases by λ as well. The requirement for constant returns to scale (CRS) in a Cobb-Douglas production function with a new input factor is given by the sum of exponents on all variables equal to 1.

In this case, Y = AKαLβMγ.

Thus, we have that α + β + γ = 1 for constant returns to scale in K, L, and M, because the sum of the exponents is 1.

If the sum of the exponents is less than 1, it indicates decreasing returns to scale. If the sum of the exponents is greater than 1, it indicates increasing returns to scale. If we take γ = 0, we obtain the production function used in class, which is Y = AKαLβ, thus α + β = 1 for constant returns to scale in K and L.

When γ = 0, the answer we get is consistent with what we learned in class. Now, we consider the constant elasticity of substitution (CES) technology, where Y = [aKα + bLα]β. The production function will have constant returns to scale (CRS) in K and L if the sum of the exponents of K and L is equal to 1.

Therefore, αβ + αβ = 1, implying 2αβ = 1.

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According to the question it took the plane 675 seconds (11 minutes and 15 seconds) to travel 3.2 km.

Travel is the act of moving from one place to another, either for leisure or business purposes. It is often associated with exploration and discovery, as well as the opportunity to experience new cultures, cuisines, and landscapes.

The velocity of the plane relative to the ground is the vector sum of the air velocity (3.0 m/s [E]) and the wind velocity (1.75 m/s [25° W of S]).

The vector sum can be calculated using the Law of Cosines and the Law of Sines.

Using the Law of Cosines, we can calculate the magnitude of the vector sum:

|v| = √(3.0 m/s)2 + (1.75 m/s)2 - 2(3.0 m/s)(1.75 m/s)cos(25°)

|v| = 4.73 m/s

Using the Law of Sines, we can calculate the angle of the vector sum:

sin(θ) = (1.75 m/s)sin(25°) / 4.73 m/s

θ = 20.9°

Therefore, the velocity of the plane relative to the ground is 4.73 m/s [20.9° W of S].

To find the time it took the plane to travel 3.2 km, we can use the equation:

t = d / v

where t is the time in seconds, d is the distance in meters, and v is the velocity in m/s.

t = 3200 m / 4.73 m/s

t = 675 s

Therefore, it took the plane 675 seconds (11 minutes and 15 seconds) to travel 3.2 km.

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Answer:

where is the question?

Answer:

Yes!

Explanation:

The slope of a velocity-time graph is indeed equal to the object's acceleration.

The NPV is equal to $150092approx.

The future value factor's inverse is the present value factor. The (1 + i) future value factor is divided by 1 to determine the present value factor. By assuming a specific rate of return, the future value determines the nominal amount that a given amount will be "worth" at a specific point in the future.

Present value of inflows-cash inflow × Present value of discounting factor(rate %,time period)

Present value of inflows = (100,000(0.84746)+(92000×0.71818)+ Present value of inflows = (120000×0.60863)+(160,000×0.51579)+

(100,000×0.43711)

Present value of inflows = $350091.56

NPV = Present value of inflows-Present value of outlows

NPV = $350091.56-$200,000

which is equal to = $150092(Approx)(A).

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The frequency of CpG (cytosine-phosphate-guanine) dinucleotides would need to be higher than expected by chance in a given DNA region in order for it to be designated as a CpG island.

Typically, a region is considered a CpG island if it is at least 200 base pairs long and has a GC content greater than 50% and an observed to expected CpG ratio of 0.6 or greater. This means that the frequency of CpG dinucleotides is higher than would be expected by chance based on the overall frequency of Cs and Gs in the genome.

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Answer:

The answers to your questions are given below

Explanation:

A. Definition of momentum.

Momentum of an object can be defined as the product of the mass of the object and its velocity. Mathematically, it expreessed as:

Momentum = mass x Velocity

From the above equation, we can derive the SI unit of momentum as follow:

Mass is measured in Kilogram (Kg)

Velocity is measured in meter per second (ms¯¹).

Momentum = mass x Velocity

Momentum = Kg x ms¯¹

Momentum = Kg•ms¯¹

Therefore, the SI unit of momentum is Kg•ms¯¹.

Bi. Determination of the force of the body from O to A.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Acceleration (a) =.?

a = v/t

a = 40/2

a = 20 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 20 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 20

F = 100 N

Therefore, the force of the body from O to A is 100 N.

Bii. Determination of the force of the body from B to C.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 10 – 6 = 4 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 4 secs.

Acceleration (a) =.?

a = v/t

a = 40/4

a = 10 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 10 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 10

F = 50 N

Therefore, the force of the body from B to C is 50 N.

Answer:

Only one parent is needed, and it is faster than sexual reproduction.

Explanation:

Sorry I'm not the best at explaining it but that's the answer.

asexual reproduction provides an advantage to the organisms that live on a rotting log by generating huge number of creatures in a very short amount of time

Asexual reproduction refers to a type of reproduction where a child is born to a single parent. The newly created people are clones of their parents since they have the same genetic makeup and physical characteristics.

Both multicellular and unicellular species can reproduce asexually. There will be no gamete fusion involved in this procedure, and the number of chromosomes will remain the same. With the exception of specific situations where there is a possibility that a rare mutation will occur, it will inherit the same genes as the parent.

The benefits of asexual reproduction are as follows:

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(c) T. The period of oscillation remains unchanged even when the mass of the bob is increased to 4.0m.

The period of oscillation of a simple pendulum is primarily determined by its length (l) and the acceleration due to gravity (g). The mass of the bob does not play a significant role in the oscillation period. The formula for the period of a simple pendulum is given by:
T = 2π √(l/g)
In this scenario, the mass of the bob is initially m, and the period is T. When the mass of the bob is replaced by one with mass 4.0m, the formula for the period remains the same since the mass does not influence the period:
T' = 2π √(l/g)
Comparing the initial period (T) and the new period (T'), we can see that both formulas are identical, which means the period remains the same:
T = T'
Hence, the correct answer is (c) T. The period of oscillation remains unchanged even when the mass of the bob is increased to 4.0m.

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Answer:

5m/s

Explanation:

If she moves her hand faster while keeping the length of the Slinky the same, the wavelength down the Slinky will decrease. This is because the wavelength of a wave is directly proportional to the speed of the wave and inversely proportional to the frequency of the wave.

When she moves her hand faster, she is increasing the frequency of the wave. This means that there will be more waves per second traveling down the Slinky. Since the length of the Slinky is staying the same, this increase in frequency means that the wavelength must decrease in order to maintain the same speed of the wave.

To visualize this, imagine a Slinky stretched out with waves traveling down it. If the waves are spaced far apart (long wavelength), they will be traveling slower. If the waves are closer together (shorter wavelength), they will be traveling faster.

So when she moves her hand faster, the waves will be closer together, resulting in a shorter wavelength. Overall, the speed of the wave remains constant while the frequency and wavelength adjust to each other in order to maintain that speed.

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Answer:

c

Explanation:

The correct statement is: "The vibrations of the fields are perpendicular to the direction of motion of the wave."

To find the correct statement among all the options, we need to know more about the Electromagnetic wave.

What is electromagnetic wave?

How does the electromagnetic wave travel?

Thus we can conclude that the option (C) is correct.

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Answer:Assuming

"m"

is a variable

|

Use

"m/s2"

as

instead

Assuming multiplication

|

Explanation:

Uniform line movement

Data:

V = 80km/h

T = 15m = 0.25 h

d = ?

We perform a conversion from minutes to hours.

           15 m * 1 h/60 m = 0.25 h

The formula for uniform motion is:

                      V = d/t

We clear for distance:

                  d = v * t

                  d = 80 km/h * 0.25 h

                  d = 20 km

The distance traveled in that time is 20 km.

The spring constant k is approximately 1520 N/m by using conservation of energy?

We can use the conservation of energy to find the spring constant k. Initially, the block has potential energy stored in the compressed spring, which is then converted to kinetic energy as the block slides across the track. At the point where the block leaves the track, all of the stored energy has been converted to kinetic energy. Neglecting air resistance, we can assume that the kinetic energy of the block at this point is equal to the potential energy stored in the spring:

\((1/2)kx² = (1/2)mv²\)

where x is the distance the spring is compressed (0.049 m), m is the mass of the block, and v is the velocity of the block when it leaves the track.

Since the block is initially at rest, we can also use kinematic equations to relate the velocity of the block to the distance it travels along the track before leaving it. The horizontal displacement of the block is unknown, so we'll call it d:

d = (1/2)at²

where a is the acceleration of the block along the track and t is the time it takes to travel that distance. The acceleration of the block is determined by the force applied by the spring:

F = kx

ma = kx

a = kx/m

Now we can substitute this expression for acceleration into the kinematic equation:

\(d = (1/2)(kx/m)t\)²

Since the block leaves the track horizontally, its vertical displacement is given by:

y = (1/2)gt²

where g is the acceleration due to gravity.

Combining these equations, we can eliminate t and solve for k:

\((k/m)(0.049)² = g(2y/g)(2d/(k/mg))²\)

Simplifying, we get:

\(k = (mg²d)/(0.049²(4y + gd))\)

Substituting the given values for m, d, and y, and the acceleration due to gravity g = 9.81 m/s², we get:

\(k = (0.4 kg)(9.81 m/s²)²(2.3 m)/[(0.049 m)²(4(0.8 m) + (9.81 m/s²)(2.3 m))]\)

k ≈ 1520 N/m

Therefore, the spring constant k is approximately 1520 N/m.

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The amount of work exerted during the lifting process is approximately 8,344.51 Joules, representing the gravitational potential energy gained as the bucket and water system is raised from the 29.3 m deep well.

To determine the amount of work performed during the lifting process, we need to calculate the gravitational potential energy gained by the bucket and water system as it is raised from the well.

The work done is equal to the change in gravitational potential energy, which can be calculated using the formula:

Work = mgh

where:

m = mass (combined mass of the water and bucket)

g = acceleration due to gravity (approximately 9.8 m/s²)

h = height (depth of the well)

Given information:

Mass of water and bucket (m) = 12.1 kg

Height of the well (h) = 29.3 m

First, let's calculate the gravitational potential energy gained by the water and bucket system:

Potential energy = mgh

Potential energy = (12.1 kg + 18.9 kg) × 9.8 m/s² × 29.3 m

Potential energy = 31 kg × 9.8 m/s² × 29.3 m

Potential energy ≈ 8,344.51 Joules

Therefore, the work performed during the lifting process is approximately 8,344.51 Joules.

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Answer:

A1 = π R^2        original area

A2 = π (R + ΔR)^2        area of hole increased in radius by ΔR

A2 - A1 = π (2 R ΔR + ΔR^2) change in area due to heating

Δ A = π 2 R ΔR           ΔR^2 is small and will be omitted

ΔR = R c ΔT        where ΔT is the temperature change

Thus the coefficient of area expansion is twice that of the coefficient of linear expansion