At a rock concert, a dB meter registered 124 dB when placed 2.5 m in front of a loudspeaker on stage. What is the sound level produced by the rock concert at 10 m, assuming uniform spherical spreading of the sound and neglecting absorption in the air? (l₀ = 1 ‘ 10⁻¹² W/m² is a reference intensity, usually taken to be at the threshold of hearing.) a. 109 Db
b. 112 dB c. 119 dB d. 129 dB e. 122 dB

Answer:

the answer is A.) Wedge

A knife to cut a piece of bread is a A. Wedge

A simple machine, any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work.

since , a wedge is a simple machine  with two inclined planes which when put together forms a sharped edge, which forms a triangular shaped tool which can be used to separate portion of  two objects .

hence , a knife to cut a piece of bread is a A. Wedge

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Answer:

Relative to Carlos the Whataburger is moving at 0 speed.

Explanation:

Carlos speed, \(V_A\) = 35 m/s

speed of another car, \(V_B\) = -25 m/s

The speed of the Whataburger, \(V_w\)  = 35 m/s since it is in the same car as Carlos.

The relative of the Whataburger to Carlos is given as;

\(V = V_A - W_w\\\\V = 35 \ m/s - 35 \ m/s\\V = 0\)

Therefore, Relative to Carlos the Whataburger is moving at 0 speed.

An accelerating universe is currently the most accepted in light of the discovery of dark energy.

A hypothesized energy known as "dark energy" acts in opposition to gravity by exerting a repellent, negative pressure. It has been proposed to explain the observable characteristics of far-off type Ia supernovae, which reveal the universe is expanding at a faster rate than usual.

Saul Perlmutter, Brian Schmidt, and Adam Riess are the recipients of the 2011 Nobel Prize in Physics. They made the stunning conclusion that the universe's expansion is speeding up as a result of their observations of far-off stars exploding.

The distance measurements utilizing type Ia supernovae (SN Ia) for the galaxies at high redshift provide the most direct and compelling evidence for the expanding cosmos powered by dark energy.

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The acceleration of the proton by using Coulomb's law is 2.806 m/s²

The acceleration of a proton can be defined by using coulombs force and centripetal acceleration. The value of coulomb force is

Fc = k.q1.q2 / d²

where Fc is coulomb force, k is Coulomb's constant, q is charge and d is distance.

Centrifugal force will also same as coulomb force, which can be determined as

F = m.a

where F is centrifugal force, m is mass and a is acceleration.

From the question above, we know that:

q1 = q2 = e = 1.602176634×10‾¹⁹ C

k = 8.988×10⁹ N⋅m²⋅C‾²

m = 1.673 x 10‾²⁴ kg

d = 7 x 10‾³ m

By combining these equations, we get

F = Fc

m.a = k.q1.q2 / d²

a = k.e² / m.d²

Substitute the parameter

a = 8.988×10⁹ . (1.6×10‾¹⁹)² / ( 1.673 x 10‾²⁴ . ( 7 x 10‾³ )² )

a = 2.806 m/s²

Hence, the acceleration of the proton by using Coulomb's law is 2.806 m/s²

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The given problem involves explaining why other current dips corresponding to excitation of higher energy levels of the mercury atom do not show up in the Franck-Hertz experiment.

Specifically, we are asked to provide a reason for the absence of these dips in the experiment.The Franck-Hertz experiment is a fundamental experiment in atomic physics that demonstrates the quantization of atomic energy levels.

In this experiment, electrons are accelerated through a mercury vapor and collide with mercury atoms, causing excitation of the atoms to higher energy levels.

The excitation is detected as a decrease in current, which corresponds to a specific energy level of the mercury atom.However, the probability of an electron experiencing an inelastic collision with a mercury atom increases with increasing electron energy. At the high density of mercury vapor used in the experiment, the probability of a 4.9-eV electron experiencing an inelastic collision is approximately 1.

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Answer:

F = 70000  N

Explanation:

Given that,

Mass of a car, m = 1400 kg

Initial speed of the car, u = 15 m/s

Finally, it hits the ground, v = 0

Time, t= 0.3 s

We need to find the force experienced by the car. Using Newton's second law of motion to find it.

F = ma

a is acceleration of the car.

\(F=\dfrac{m(v-u)}{t}\\\\F=\dfrac{1400\times (0-15)}{0.3}\\\\=-70000\ N\)

So, the force experienced by the car has a magnitude of 70000  N.

Infants typically begin to make vowel-like sounds at around 2 to 3 months of age. These sounds are often referred to as cooing or gooing, and are an important part of early language development.                                                                                  

As they continue to grow and develop, infants will begin to experiment with different sounds, including consonants, and will eventually begin to form words and sentences. It is important for caregivers to interact and respond to these sounds, as it helps to build a foundation for language acquisition and communication.
These initial sounds are the building blocks for more advanced language skills, and they help infants to practice their vocalizations while also engaging in social interactions with their caregivers. As infants grow and develop, these sounds will gradually evolve into more complex speech patterns and, eventually, words and sentences.

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ANSWER

EXPLANATION

We want to find the magnitude of the electric field.

To do this, we have to apply the formula for electric field:

where F = force exerted on the charged particle

q = electric charge on the particle

Hence, the magnitude of the electric field is:

The correct answer is the first option.

Answer:

D

Explanation:

These all can impact the magnetic properties

The unit tangent vector T(t) for the curve defined by r(t) = (e², 2t, e) at t = 2 is \(\[T(2) = \left(\frac{e^2}{\sqrt{e^4 + 16 + e^2}}, 4, e\right)\]\). The unit normal vector N(t) for the curve at \(\[N(2) = \left(\frac{-2e^2}{\sqrt{4e^4 + 1}}, 1, 0\right)\]\).

The normal acceleration ar at \(\[ar(2) = \frac{\sqrt{4e^4 + 1}}{\sqrt{e^4 + 16 + e^2}}\]\). The tangential acceleration at t = 2 is aT(2) = 0 since the curve is defined as a straight line and has no curvature.

To find the unit tangent vector T(t), we take the derivative of the position vector r(t) with respect to t and normalize it by dividing by its magnitude. The derivative of \(\[T(t) = \frac{(e^2, 4, e)}{\sqrt{e^4 + 16 + e^2}}\]\).

To find the unit normal vector N(t), we differentiate T(t) with respect to t and normalize the resulting vector. The derivative of T(t) is (0, 0, 0), which means the curve is a straight line. Therefore, N(t) is constant and given by \(\[N(t) = \frac{(-2e^2, 1, 0)}{\sqrt{4e^4 + 1}}\]\).

The normal acceleration ar at t = 2 is the magnitude of the derivative of T(t) with respect to t, which simplifies to \(\[\frac{\sqrt{4e^4 + 1}}{\sqrt{e^4 + 16 + e^2}}\]\).

Since the curve is a straight line, there is no change in the direction of the velocity vector, and therefore, the tangential acceleration aT is zero.

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The three options are 1,3 and 5 Moving the balls closer together. The distance decreases and forces increase.

The gravitational force ia s type of force has the ability attracts any two objects with mass. Gravitational force tries to pull two masses towards each other.

The value of the gravitational force is given by;

\(F_g=\frac{ Gm_ 1m_2}{r^2}\)

It is observed that the gravitational force is directly propotional to the product of mass and inversly propotional to the square of the distance between them.

So, the correct options are :

(1) Moving the balls closer together. The distance decreases and forces increase.

(3) Wrapping the soccer ball in layers of duct tape will also increase force because the mass will increase.

(5) Similarly, putting the baseball in a plastic case will increase mass, and hence force increases.

Hence the three options are 1,3 and 5.

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Both balls soon after they left her palm experienced the same amount of acceleration, but in opposite directions.

We define acceleration a as the rate of change of velocity with respect to time for linear motion:

a = dv/dt = d²x/dt²

According to Newton's second law, a force F is required to accelerate a mass m:

F= ma

The forces exerted on the ball govern its acceleration. There is just one force acting on both balls at the moment they are released from the student's hand: gravity. Therefore, the amount and direction of the acceleration of both balls are the same:

F = mg with,

|g| = 9.81 m/s², pointing straight down.

Both balls soon after they left her palm experienced the same amount of acceleration, but in opposite directions.

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Explanation:

∑F = ma

100 N = (10 kg) a

a = 10 m/s²

Answer:

a) i) In the first image we can see that almost the whole island is covered with forest. While in the second one, we can see that near the edges of the island the amount of forest cover has ben decreased. This may be because is easier to cut the trees near the shore of the island.

ii) There are different motives to cut the trees, one may be to build constructions. People need to remove the trees in an area in order to be able to build in there. Also, the trees can be used in a lot of different ways as raw materials.

b) i) Less forest cover also means that there is a smaller habitable area for the local life (animals, insects, etc...). Then the animals need to be more "cramped", and this can affect greatly the life of them.

ii) There will be less food and fewer natural resources for the locals.

The speed of the moving train is 28.7 m/s when the conductor on the stationary train hears a 3.3 Hz beat frequency.

The beat frequency is the difference between the frequencies of the two whistles. In this case, the beat frequency is 3.3 Hz. We know that the frequency of the emitted whistle is 439 Hz.

Therefore, the frequency of the whistle heard by the conductor on the stationary train is 439 Hz - 3.3 Hz = 435.7 Hz.

Using the Doppler effect formula, we can calculate the speed of the moving train.  

Speed of sound = 343 m/s (approx.)
Frequency of the whistle heard by the stationary train = 435.7 Hz
Frequency of the emitted whistle = 439 Hz
Speed of the moving train = (Speed of sound x Beat frequency) / (Frequency of the emitted whistle)
Speed of the moving train = (343 m/s x 3.3 Hz) / (439 Hz - 3.3 Hz)
Speed of the moving train = 28.7 m/s (approx.)

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Answer:

1) Acids have a sour taste , Bases have a bitter taste.

2) Acids turn blue litmus paper into red , Bases turn red litmus paper into blue.

3) Acids react with most metals to form Hydrogen gas but only a few base react with a few metals to form Hydrogen gas

4) Both will conduct electricity. Both acids & bases are good electrolytes. Strong acids & bases conduct more electricity than that of weak acids & bases

Fill in the blanks with the properties of acids and bases as follows:

The properties of acids are as follows:

Therefore, fill in the blanks with the properties of acids and bases are well described above.

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The three fundamental aspects of an ideal training progression are competency, strength, and power. These three aspects are crucial for building a solid foundation for physical fitness and achieving one's fitness goals.

By focusing on these three aspects in a training progression, one can improve their overall fitness and reduce the risk of injury. All three components need to be taken into account when creating an effective training program.

Hence, the correct option is c.

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a 1.25 kg block is attached to a spring with spring constant 17.0 n/m . while the block is sitting at rest, a student hits it with a hammer and almost instantaneously gives it a speed of 46.0 cm/s .The amplitude of the subsequent oscillations 48.13 cm/s

a 1.25 kilogram block is fastened to a spring with a 17.0 newtons per meter spring constant. Given that K is equal to 14 Newtons per meter and mass equals 10.5 kg. The block is then struck with a hammer by a student while it is at rest, giving it a speedo of 46.0 cm for a brief period of time. The required energy provided by the hammer, which is half mv squared, is transformed into potential energy as a result of the succeeding oscillations. This is because we know that energy is still available for consultation. So access the amplitude here from here. He will therefore be equal to and by. Consequently, the Newton's spring constant is 14 and the value is 10.5. The velocity multiplied by 0.49

Speed at X equals 0.35 into amplitude, or vice versa. At this point, the spirit will equal half of K X 1 squared plus half. Due to the fact that this is the overall energy, square is equivalent to half of a K square or an angry square. amplitude is 13 and half case 14 x one is 0.35. calculate that is equal to initial velocities of 49 squares and masses of 10.5. This will be divided in half and start at about 10.5 into the 49-square-minus-14. 13.42 into the entire square in 20.35. dividing by 10.5 and taking the square as a result. 231 6.9 Six centimeters per square second. 10.5 into 49 sq. 14. 2 into a 13.42 square entire. then subtract 10.5 from the result to get the square. So that is 48.13cm/s.

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This is incomplete question Complete Question is:

a 1.25 kg block is attached to a spring with spring constant 17.0 n/m . while the block is sitting at rest, a student hits it with a hammer and almost instantaneously gives it a speed of 46.0 cm/s . what are The amplitude of the subsequent oscillations?

The bicyclist must move 0.85 meters backward to reach the nearest point of destructive interference.

To determine the distance the bicyclist needs to move backward, we can use the concept of interference. Constructive interference occurs when the path length difference between the two sources is an integer multiple of the wavelength, while destructive interference occurs when the path length difference is a half-integer multiple of the wavelength. Given that the frequency is 675 Hz and the speed of sound is 343 m/s, we can calculate the wavelength (λ) using the formula: λ = v / f. Then, the path length difference between the two horns is 2r. The bicyclist needs to move backward by λ/2 to reach the nearest point of destructive interference, which is 0.85 meters (λ/2 = (2r - λ/2)).

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We are asked to determine the magnitude of the force that acts parallel to the nail. To do that we will add the torque that acts on the point of contact. First, we draw a free-body diagram of the situation:

We have decomposed the force of the nail into its horizontal and vertical components. The horizontal component does no torque since there is no distance parallel to the force to the point of contact.

Now, we add the torques. We consider counterclockwise as positive:

Since we consider the moment before there is no angular acceleration the sum of torques adds up to zero:

Now, we determine the value of Ry as a function of "R" using the trigonometric function cosine:

Now, we multiply both sides by "R":

Now, we substitute in the sum of torques:

Now, we solve for "R". First, we add "30F" to both sides:

Now, we divide both sides by 5cm:

Now, we divide both sides by cosine:

Now, we substitute the values:

Solving the operations:

Therefore, the force on the nail is 1042.8 Newtons.

Answer: D

Explanation:

cause i got it right

Answer:

it is dddd

Explanation:

Answer:

False,  the given equation is not balanced.

Explanation:

The given equation is:

Na(g) + 2HCl(g) → H₂(g) + 2NaCl(s)

And it is not balanced, the number of atoms of Na is not the same on both sides of the equation.

The balanced equation is:

2Na(g) + 2HCl(g) → H₂(g) + 2NaCl(s)          

Now, the given equation is balanced, we have the same number of atoms on both sides of the equation.

Therefore, the answer is false, the given equation is not balanced.

I hope it helps you!

The crosswords based on the information will be:

5. Mechanical energy

Work

Solar radiation

Watts (W)

Wind turbine

Hydroelectric power

Thermal energy

Capacitor

Increase its speed/velocity

Electromagnetic energy

Down

Conservation of energy

Lever

Newtons (N)

Kinetic energy

Foot-pounds (ft-lb) or British Thermal Units (BTUs)

Power

Geothermal energy

Field

Increase its height

Joules (J)

Friction

Radiant energy

Potential energy

Lever

Nuclear energy

Mass

Mechanical energy (kinetic energy or potential energy) is the energy of either an object in motion or the energy that is stored in objects by their position.

Mechanical energy is also a driver of renewable energy. Many forms of renewable energy rely on mechanical energy to adequately produce power or convert energy.

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The final volume of water in the container after increasing the temperature is 203.8 m³.

From the given,

The initial volume of water (Vο) = 200 cm³

Initial temperature = 4°C = 4+273 = 277K

Final temperature = 95°C = 273+95 = 368 K

Volume expansion co-efficient = 210×10⁻⁶(°C)⁻¹

Final volume =?

β = 1/Vο (ΔV/ΔT),  β represents the volume expansion coefficient, ΔV change in volume, ΔT is the change in temperature, and Vο is the initial volume.

ΔV = β×Vο×ΔT

     = 210×10⁻⁶×200×(368-277)

    =  210×10⁻⁶×200×91

ΔV = 3.83 m³

ΔV = final volume - initial volume

final volume = ΔV + 200

                    = 3.82 +200

                    = 203.82 m³

Final volume = 203.82 m³.

Thus, the final volume of the water is 203.82 m³.

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Answer:

1,211.1 kg.

Explanation:

the force of gravity is less on the moon than on earth, so if the man can lift 200kg on earth, he could lift a greater amount on the moon because there is less resistance from gravity.

To know the amount of mass he can lift on the moon, we first need to know the amount of weight that is equivalent to those 200kg here on earth. This because the weight of the object is equal to the force that must be applied to lift it, and that force is applied by the man and it will be the same here and on the moon.

We calculate weight using the formula:

\(w=mg\)

where \(w\) is the weight of the object (the force with which the earth attracts the object) \(m\) is the mass and g the acceleration of gravity.

so

\(w=200g\)

for earth the acceleration due to gravity is:  \(g=9.81m/s^2\)

thus:

\(w=(200kg)(9.81m/s^2)\\w=1962N\)

now we use this value to calculate the mass he can lift on the moon, since for the moon \(g=1.62m/s^2\).

we use the same equation, w =mg substituting w = 1962N and \(g=1.62m/s^2\):

\(w=mg\\\\1962N=m(1.62m/s^2)\\\\m=\frac{1962N}{1.62m/s^2}\\\\ m=1,211.1kg\)

he can lift 1,211.1 kg.

You can also find the result using the approximate value of the acceleration of gravity on the moon as g/6, where g is the acceleration on earth.

Explanation:

t = usin©/g

Where t is the time to reach the maximum height

Time spent in air is T = 2t

Hence, T = 2usin©/g

T = 2 x 20 x sin 65°/ 9.8

T = 3.69s

The mass of the silver is 289.275 x 10³ kg.

If you tried to smuggle silver ingots by completely filling a tote bag, whose dimensions are 50 cm x 29 cm x 19 cm, the density of silver is 10.5 x 10³ kg/m³

What would its mass be?

The formula for density is d = M/V

d = density (ρ)

M = mass (kg)

V = volume  (cm³)

First determine the volume

V =  Length x Width x Height

= 50 cm x 29 cm x 19 cm

= 27.550 cm³

The formula for density is d = M/V

So, the mass (M) is:

d x V

= 10.5 x 10³ kg/m³ x 27.550 cm³

= 289.275 x 10³ kg

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