a child swings back and forth on a swing suspended by 3.3 m -long ropes. find the turning-point angles if the child has a speed of 0.80 m/s when the ropes are vertical.

-50F is the air temperature at which the speed of a sound wave is closest to 1,000 feet per second. It is option D.

The speed of a sound wave depends on the temperature of the medium through which it travels. The formula for calculating the speed of sound in air is given by: v = 331 m/s + 0.6 m/s °C × t

t = temperature in degrees Celsius  

v = velocity of the sound wave in meters per second.

Therefore, to answer the question, we need to convert the temperatures from Fahrenheit to Celsius and use the above formula to determine the velocity of the sound wave at each temperature.

A. -46F = -43.33°C

Speed of sound = 331 + 0.6 x (-43.33)≈ 304.4 m/s

B. -48F = -44.44°C

Speed of sound = 331 + 0.6 x (-44.44)≈ 303.6 m/s

C. -49F = -45°C

Speed of sound = 331 + 0.6 x (-45)≈ 303 m/s

D. -50F = -45.56°C

Speed of sound = 331 + 0.6 x (-45.56)≈ 302.5 m/s

Therefore, the air temperature at which the speed of a sound wave is closest to 1,000 feet per second is option D.-50F.

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All supernova explosions leave stars in the same condition after the process has finished which is false.

Supernova explosions do not leave stars in the same condition after the process has finished. Supernovae are incredibly powerful explosions that occur at the end of a massive star's life or in the aftermath of a white dwarf's accretion. The outcome of a supernova depends on various factors, such as the mass of the star and the nature of the explosion. There are two main types of supernovae: Type I and Type II.

In a Type I supernova, the star is completely destroyed, leaving behind either a neutron star or a black hole. These explosions occur in binary star systems where a white dwarf accumulates matter from a companion star, eventually reaching a critical mass and triggering a runaway nuclear reaction.

In a Type II supernova, the massive star collapses under its own gravity, resulting in a powerful explosion. After the explosion, what remains can vary. It could leave behind a neutron star or even a black hole. The remnants may also include a rapidly expanding cloud of gas and dust called a supernova remnant, which can enrich the surrounding space with heavy elements.

Therefore, it is incorrect to say that all supernova explosions leave stars in the same condition after the process has finished. The specific outcome depends on various factors and can lead to the formation of different celestial objects.

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a. The potential at 5.50 cm from the center of the sphere is 9.00 x [tex]10^7[/tex] V.

b. The potential at 30.0 cm from the center of the sphere is 1.65 x [tex]10^8[/tex] V.

c. The potential at 16.0 cm from the center of the sphere is 2.47 x [tex]10^8[/tex] V.

To find the value of the potential at different distances from the center of the sphere, we can use the equation for the electric potential of a uniformly charged sphere.

Given:

Total electric charge (Q) = 5.50 nC

Radius of the sphere (R) = 30.0 cm = 0.30 m

a) To find the potential at 5.50 cm from the center of the sphere:

Distance from the center of the sphere (r) = 5.50 cm = 0.055 m

The equation for the electric potential of a uniformly charged sphere is:

V = k × Q / r

where V is the potential, k is the Coulomb's constant (8.99 x [tex]10^9[/tex] N m²/C²), Q is the total charge, and r is the distance from the center of the sphere.

Substituting the given values into the equation:

V = (8.99 x [tex]10^9[/tex] N m²/C²) × (5.50 x [tex]10^{-9[/tex] C) / 0.055 m

Calculating the value:

V = 9.00 x [tex]10^7[/tex] V

Therefore, the potential at 5.50 cm from the center of the sphere is 9.00 x [tex]10^7[/tex] V.

b) To find the potential at 30.0 cm from the center of the sphere:

Distance from the center of the sphere (r) = 30.0 cm = 0.30 m

Using the same equation as above:

V = (8.99 x [tex]10^9[/tex] N m²/C²) × (5.50 x [tex]10^{-9[/tex] C) / 0.30 m

Calculating the value:

V = 1.65 x [tex]10^8[/tex] V

Therefore, the potential at 30.0 cm from the center of the sphere is 1.65 x [tex]10^8[/tex] V.

c) To find the potential at 16.0 cm from the center of the sphere:

Distance from the center of the sphere (r) = 16.0 cm = 0.16 m

Using the same equation as above:

V = (8.99 x [tex]10^9[/tex] N m²/C²) × (5.50 x [tex]10^{-9[/tex] C) / 0.16 m

Calculating the value:

V = 2.47 x [tex]10^8[/tex] V

Therefore, the potential at 16.0 cm from the center of the sphere is 2.47 x [tex]10^8[/tex] V.

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The crank OB is horizontal and has a clockwise angular velocity of 0.8 rad/sec. The objective is to find the speed of the guide roller A and the angular velocity of the connecting rod AB link.

To solve this problem, let's first draw the mechanism diagram. [tex]\frac{d\theta_{1}}{dt}[/tex] and [tex]\frac{d\theta_{2}}{dt}[/tex] are the angular velocities of OB and AB, respectively. We can apply the kinematic equations to find these unknowns.

In this case, the kinematic equations of the mechanism are Vb = Va + AB * [tex]\frac{d\theta_{2}}{dt}[/tex] (1)0 = AB * cos β - OA * [tex]\frac{d\theta_{1}}{dt}[/tex] (2.).

Now, we can evaluate [tex]\frac{d\theta_{1}}{dt}[/tex] and [tex]\frac{d\theta_{2}}{dt}[/tex] using the given angular velocity of crank OB.

It is given that [tex]\frac{d\theta_{1}}{dt}[/tex] = 0.8 rad/sec.

Using equation (2), we can obtain AB = OA * cos β / [tex]\frac{d\theta_{1}}{dt}[/tex].

Putting the value of [tex]\frac{d\theta_{1}}{dt}[/tex] = 0.8 rad/sec, OA = 60 mm and β = 60° in equation (2),

We get:AB = 60 * cos 60 / 0.8 = 43.3 mm.

Now, using equation (1), We can find the speed of the guide roller Va as Vb = Va + AB * [tex]\frac{d\theta_{2}}{dt}[/tex]Vb - Va = AB * [tex]\frac{d\theta_{2}}{dt}[/tex]Va = Vb - AB * [tex]\frac{d\theta_{2}}{dt}[/tex].

We know that Vb = R * [tex]\frac{d\theta_{1}}{dt}[/tex] = 60 * 0.8 = 48 mm/sec.

Hence,Va = 48 - 43.3 * [tex]\frac{d\theta_{2}}{dt}[/tex].

Now, we need to find [tex]\frac{d\theta_{2}}{dt}[/tex]. We can find it using the kinematic equation of link AB, which is given as AB * sin β * [tex]\frac{d\theta_{2}}{dt}[/tex] = Va.

But, we don't know the value of Va yet. So, we can use the velocity diagram of the mechanism to relate the velocities of points A and B.

Using the vector law of addition of velocities, we can write Va^2 = (Vb cos β)^2 + (Vb sin β - R [tex]\frac{d\theta_{1}}{dt}[/tex])^2Putting the values of Vb, β and R, we get: Va^2 = (48 cos 60)^2 + (48 sin 60 - 60 * 0.8)^2Va = 52.4 mm/sec.

Now, putting the value of Va in the kinematic equation of link AB, we get AB * sin β * [tex]\frac{d\theta_{2}}{dt}[/tex] = 52.4d[tex]\theta_{2}[/tex] / dt = 52.4 / (43.3 * sin 60)d[tex]\theta_{2}[/tex] / dt = 0.639 rad/sec.

Hence, the speed of the guide roller A in the slot is 52.4 mm/sec and the angular velocity of the AB link is 0.639 rad/sec.

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Therefore, the focal length of the converging lens is approximately 9.33 cm or 21 cm (rounded to the nearest whole number).

To determine the focal length of the converging lens, we can use the lens formula:

1/f = 1/v - 1/u

where f is the focal length, v is the image distance from the lens, and u is the object distance from the lens.

Given that the object is placed 28 cm in front of the lens (u = -28 cm) and the image is formed 14 cm behind the lens (v = 14 cm), we can substitute these values into the lens formula:

1/f = 1/14 - 1/(-28)

Simplifying the equation:

1/f = 1/14 + 1/28

Finding a common denominator:

1/f = 2/28 + 1/28

Combining the fractions:

1/f = 3/28

Inverting both sides of the equation:

f = 28/3

Converting the fraction to decimal form:

f ≈ 9.33 cm

Therefore, the focal length of the converging lens is approximately 9.33 cm or 21 cm (rounded to the nearest whole number).

The focal length of the converging lens is approximately 21 cm.

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A radio receiver can detect signals with electric field amplitudes as small as 350 μV/m, the intensity of the smallest detectable signal is approximately [tex]\(6.17 \times 10^{-21} \, \text{W/m}^2\)[/tex].

The intensity (I) of an electromagnetic wave is related to its electric field amplitude (E) by the formula:

[tex]\[ I = \frac{1}{2} \varepsilon_0 c E^2 \][/tex]

Where:

[tex]\( \varepsilon_0 \)[/tex] = vacuum permittivity ([tex]\(8.854 \times 10^{-12} \, \text{F/m}\)[/tex])

c = speed of light in vacuum ([tex]\(3.00 \times 10^8 \, \text{m/s}\)[/tex])

E = electric field amplitude of the signal

Given that the electric field amplitude (E) is [tex]\(350 \, \mu\text{V/m}\)[/tex], we need to convert it to volts per meter before using it in the formula. [tex]\(1 \, \mu\text{V} = 10^{-6} \, \text{V}\)[/tex], so:

[tex]\[ E = 350 \, \mu\text{V/m} \\\\= 350 \times 10^{-6} \, \text{V/m} \][/tex]

Now we can calculate the intensity (I) using the formula:

[tex]\[ I = \frac{1}{2} \varepsilon_0 c E^2 \][/tex]

Plug in the values:

[tex]\[ I = \frac{1}{2} \times (8.854 \times 10^{-12} \, \text{F/m}) \times (3.00 \times 10^8 \, \text{m/s}) \times (350 \times 10^{-6} \, \text{V/m})^2 \][/tex]

Calculate the intensity (I):

[tex]\[ I \approx 6.17 \times 10^{-21} \, \text{W/m}^2 \][/tex]

Thus, the intensity of the smallest detectable signal is [tex]\(6.17 \times 10^{-21} \, \text{W/m}^2\).[/tex]

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Answer:

Efficiency of the inclined plane is 56%

Explanation:

efficiency = (work output / work input) x 100%

efficiency = ([load force x load distance] x [effort force x effort distance]) x 100%

efficiency = (250 kg x 10 m) / (180 kg x 25 m) x 100%

efficiency = (2500kg/m) / (4500kg/m) x 100%

efficiency = 0.555 = 0.56 x 100%

efficiency = 56%

Answer:

Y = 4.775 x 10⁹ Pa = 4.775 GPa

Explanation:

First, we calculate the stress on the rod:

[tex]stress = \frac{Force}{Area} = \frac{3000\ N}{\pi r^2} \\\\stress = \frac{3000\ N}{\pi (0.01\ m)^2}\\\\stress = 9.55\ x\ 10^6\ Pa = 9.55 MPa\\[/tex]

Now, we calculate the strain:

[tex]strain = \frac{Change\ in Length}{Original\ Length}\\\\strain = \frac{0.501\ m - 0.5\ m}{0.5\ m}\\\\strain = 0.002\\[/tex]

Now, we will calculate the Young's Modulus (Y):

[tex]Y = \frac{stress}{strain}\\\\Y = \frac{9.55\ x\ 10^6\ Pa}{0.002} \\[/tex]

Y = 4.775 x 10⁹ Pa = 4.775 GPa

Answer:

11 cm and concave

Explanation:

edge 2021

Answer:

it is -21, The top part is correct it is only the second part this is the first part.

Explanation:

As the time needed to run up a flight of stairs decreases, the power initially increases and then decreases.

The power generated during an activity can be calculated using the equation: Power = Work / Time. In the context of running up a flight of stairs, the work done is the force exerted to overcome gravity and move the body vertically against it. When the time needed to complete the task decreases, it means the individual is able to generate more power.

Initially, as the person improves their running ability and becomes more efficient, they can complete the task in less time. This reduction in time indicates an increase in power output since the work done remains relatively constant. The individual is exerting more force in a shorter amount of time, resulting in higher power.

However, there is a limit to how much power a person can generate. As the person continues to improve their running speed, they reach a point where their power output plateaus or even decreases. This decline can occur due to various factors, such as muscle fatigue or biomechanical limitations. At this stage, further decreases in time may not be achievable without sacrificing power output. Therefore, the power initially increases as time decreases, but eventually levels off or decreases as the person reaches their physiological limits.

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Answer:

3 m/s²

Explanation:

Initial Velocity, u = 18

Final velocity, v = 36

Time, t = 6 seconds

Acceleration is the change in velocity of a body with time. It obtained using the relation :

Acceleration = (v - u) / t

Acceleration = (36 - 18) / 6

Acceleration = 18 / 6

Acceleration = 3m/s²

Hence, acceleration of the skier is 3m/s²

Answer:

When the angle between two vectors A and B is 0 degrees, they are parallel to each other and pointing in the same direction. In this case, the resultant of the two vectors will be the sum of the magnitudes of A and B, and it will also be parallel to both A and B.

When the angle between two vectors A and B is 90 degrees, they are perpendicular to each other. In this case, the resultant of the two vectors will be the vector that connects the initial point of A to the terminal point of B (or vice versa). The magnitude of the resultant vector can be found using the Pythagorean theorem: |R| = sqrt(|A|^2 + |B|^2), where |A| and |B| represent the magnitudes of vectors A and B, respectively.

When the angle between two vectors A and B is 180 degrees, they are pointing in opposite directions. In this case, the resultant of the two vectors will be the difference between the magnitudes of A and B, and it will be in the direction of the larger vector. The magnitude of the resultant vector can be found by subtracting the magnitude of the smaller vector from the magnitude of the larger vector: |R| = |A| - |B| if |A| > |B| or |R| = |B| - |A| if |B| > |A|.

To determine the resultant of two vectors A and B, it is necessary to know the magnitudes of the vectors and the angle between them. In your question, you provided the angles between A and B (0 degrees, 90 degrees, and 180 degrees), but you did not specify the magnitudes of the vectors.

Without the magnitudes of vectors A and B, it is not possible to calculate the exact resultant. The resultant vector depends on both magnitude and direction, and without knowing the magnitudes, it is not possible to determine the resultant accurately.

If you provide the magnitudes of vectors A and B, I can help you calculate the resultant for each angle.

The maximum induced electromotive force (emf) in the AC generator is approximately 3.25 volts.

To find the maximum induced electromotive force (emf) in the AC generator, we can use the equation:

emf = N * ΔΦ / Δt

Where:

emf is the induced electromotive force

N is the number of turns in the coil

ΔΦ is the change in magnetic flux

Δt is the time interval

First, we need to calculate the change in magnetic flux (ΔΦ). The magnetic flux through a coil is given by:

Φ = B * A

Where:

B is the magnetic field

A is the area of the coil

The area of the coil can be calculated using the formula:

A = π * r²

Where:

r is the radius of the coil

Substituting the values:

A = π * (0.05 m)²

A = 0.00785 m²

ω = 500 rpm = (500/60) rev/s

Δt = 1 / ω

Δt = 1 / (500/60) s

Δt = 0.12 s

Now, we can calculate the change in magnetic flux (ΔΦ) by multiplying the magnetic field (B) by the area (A):

ΔΦ = B * A

ΔΦ = (0.250 T) * (0.00785 m²)

ΔΦ = 0.0019625 Wb

emf = N * ΔΦ / Δt

emf = (200 turns) * (0.0019625 Wb) / (0.12 s)

emf ≈ 3.25 V

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Increasing number of photons per second striking the surface and increasing the frequency of the incident light lead to increase in maximum kinetic energy of ejected electrons in the photoelectric effect.

Increasing the number of photons per second striking the surface:

The maximum kinetic energy of the ejected electrons depends on the total energy transferred to the electrons by the incident photons. Increasing the number of photons per second increases the total energy transferred, resulting in an increase in the maximum kinetic energy of the ejected electrons.

Increasing the frequency of the incident light:

The maximum kinetic energy of the ejected electrons is directly proportional to the frequency of the incident light. According to the equation E = hf, where E is the energy of a photon, h is Planck's constant, and f is the frequency of the light, increasing the frequency of the incident light increases the energy of each photon. This, in turn, leads to an increase in the maximum kinetic energy of the ejected electrons.

Using photons whose frequency fo is less than Wo/h, where Wo is the work function of the metal and h is Planck's constant:

If the frequency of the incident light is less than the threshold frequency (fo) required to overcome the work function of the metal, no electrons will be ejected regardless of the intensity or number of photons. Therefore, using photons with a frequency less than the threshold frequency does not lead to an increase in the maximum kinetic energy of the ejected electrons.

Selecting a metal that has a greater work function:

The work function of a metal represents the minimum amount of energy required to eject an electron from its surface. Selecting a metal with a greater work function would result in a higher energy threshold for electron ejection. While it affects the threshold for electron ejection, it does not directly influence the maximum kinetic energy of the ejected electrons.

Increasing the number of photons per second striking the surface and increasing the frequency of the incident light lead to an increase in the maximum kinetic energy of the ejected electrons in the photoelectric effect. However, using photons with a frequency less than the threshold frequency and selecting a metal with a greater work function do not contribute to an increase in the maximum kinetic energy of the ejected electrons.

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The change in potential energy of the spring system is 15.6 x 10³J.

Mass of the disc, m = 20 kg

Velocity of the disc, v = 3 m/s

Spring constant of the spring, k = 200 N/m

Angular displacement of the disc, x = 2 revolutions = 2 x 2π = 4π radians

The potential energy that is stored when an elastic object is stretched or compressed by an external force, such as the stretching of a spring, is known as elastic potential energy. It is equivalent to the effort required to extend the spring, which is dependent on both the length of the stretch and the spring constant k.

The expression for the elastic potential energy of the spring is given by,

PE = 1/2 kx²

PE = 1/2 x 200 x (4π)²

PE = 1.57 x 10⁴J

The kinetic energy of the disc is given by,

KE = 1/2 mv²

KE = 1/2 x 20 x 3²

KE = 90 J

Therefore, the change in potential energy is,

E = 1.57 x 10⁴- 90

E = 15.6 x 10³J

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Answer:

a unit of mass or weight equaling one thousand grams

The appropriate symbol to use for the answer is "CI," which stands for confidence interval.

What is confidence interval?

A confidence interval is a range of values that provides an estimate of an unknown population parameter, such as the mean body temperature of all healthy humans in this case.

In the given question, we are asked to construct a 99% confidence interval estimate of the mean body temperature of all healthy humans. A confidence interval is typically denoted by "CI" followed by the level of confidence, which in this case is 99%. It helps in quantifying the uncertainty associated with our estimate and provides a range rather than a single point estimate.

Hence, the appropriate symbol to use for the answer is "CI" to represent the confidence interval estimate of the mean body temperature of all healthy humans.

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Answer:  TRUE /   IT IS TRUE

Explanation:

Answer:

[tex]\frac{60kgm}{s}[/tex]

Explanation:

momentum = mass * velocity

= 20kg * 3m/s

= 60kgm/s

Answer: Biotic

Explanation: Because it's bacteria.

The height of the cannon where the objects are launched from is 18 feet.

The canons of page construction are historical reconstructions, based on careful measurement of extant books and what is known of the mathematics and engineering methods of the time, of manuscript-framework methods that may have been used in Medieval- or Renaissance-era book design to divide a page into pleasing proportions. Since their popularization in the 20th century, these canons have influenced modern-day book design in the ways that page proportions, margins and type areas (print spaces) of books are constructed.

To determine the height of the cannon where the objects are launched from, we need to find the value of "h" when "t" is equal to zero.

Given the equation: h = (-1/5)×t^2 + 5×(t) + 18

Substituting t = 0 into the equation, we have:

h = (-1/5)×(0)^2 + 5(0) + 18

= 0 + 0 + 18

= 18

Therefore, the height of the cannon where the objects are launched from is 18 feet.

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The magnification of the eyepiece is 19.

The magnification of an eyepiece of a microscope is,

Magnification = Near-point distance / Focal length of eyepiece

Given that,

Near-point distance = 38 cm

Focal length of eyepiece = 2 cm

Substituting the values,

Magnification = Near-point distance / Focal length of eyepiece

Magnification = 38 / 2

Magnification = 19

Therefore, the magnification of the eyepiece is 19.

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Answer:

Geomagnetic Field

Explanation:

This soil sample is one that is primarily clay, with some portions of silty clay and sand.

It has little of the clay loam category, that has a balanced mixture of clay, silt, and sand.

The soil triangle shows soil texture using sand, silt, and clay. Based on given percentages, soil sample has 40% silt, 40% sand, and 20% clay. It's silty sand or sandy loam soil.

Clay loam soil has a balanced blend of clay, silt, and sand. Moderate water-holding, good drainage, favorable nutrient retention. Sandy clay is a mixture of sand and clay. Retains sandy soil traits with better water hold from clay.

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