Sound waves travel through liquids tend to move faster than sound waves traveling through

Metals are both good heat conductors and good electrical conductors because of the looseness of outer electrons in metal atoms

_________________________

Unlike nonmetals that are insulators, most metals are both good heat conductors and good electrical conductors. This is because within a solid metal there is one or more outer electrons in each atom that become detached and can move freely through the solid metal, but what about the other electrons?  Well, the y remain bound to the positively charged nuclei, and bound within the material in almost fixed positions. On the other hand, insulators are material having few, very few or no electrons that are allowed to move freely through  the material.

Answer:

looseness of outer electrons in metal atoms

Explanation:

Unlike in insulators the valance electrons in metals are free to roam inside the boundaries of the metal slab. These electrons are called free electrons.

These electrons are free to move because there is no gab between their valance band and conduction band.

Since they are free to move they can transfer charges easily and be a good conductor.

Also heat exchange takes place when one electron collides with another moving electron or a stationary atom.

This is why metals are both good heat conductors and good electrical conductors.

In Burglar alarm, LDR acts an AND gate.

Answer: C

Explanation

The LDR is light dependent resistor. The principle used in the working of LDR is that the resistance is inversely proportional to the intensity of light falling on the diode.

In burglar alarm, LDR diode is combined with an IC 555.

Normally an LED source is made to be incident on the LDR diode with same intensity such that the resistance will be maintained constant.

As the LDR is connected with IC, the voltage will be high when light is falling on the diode.

The IC will give only two output states that is high and low. This confirms that LDR in burglar alarm act as AND gate.

As the thief enters and crosses the LED light, the intensity of the light falling on the diode will decrease leading to decrease in the voltage which will cause the alarm to beep.

In a Burglar alarm, LDR acts as an AND gate. Option C is correct. This is further explained below.

Generally, an alarm is simply defined as a danger signal, generally in the form of loud noise or flashing light: If there's a problem, pull the safety cord to sound the alarm.

In conclusion, LDR serves as an AND gate in a security alarm.

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Answer:

6.14 m

Explanation:

The motion of the object is divided into three parts:

- Part 1: the object moves with speed

v = +0.9 m/s (the positive sign means positive x-direction)

for t = 3.6 s

Therefore, the distance covered is

[tex]d_1 =vt=(0.9 m/s)(3.6 s)=3.24 m[/tex]

- Part 2: the object stops for 4.7 s, so during this time the distance travelled by the object is zero.

- Part 3: the object moves with speed

v = -1 m/s (negative sign means negative x-direction)

for a time of

t = 2.9 s

We are only concerned in the distance travelled, so we can ignore the negative sign, and the distance covered in this part is

[tex]d_3 = vt=(1 m/s)(2.9 s)=2.90 m[/tex]

So, the total distance covered is

[tex]d=d_1+d_2+d_3=3.24 m+0 +2.90 m=6.14 m[/tex]

Answer:

[tex]1.33\Omega[/tex]

Explanation:

The equivalent resistance of three resistors connected in parallel is given by:

[tex]\frac{1}{R_T} = \frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}[/tex]

where in this problem we have

[tex]R_1 = 4.0\Omega[/tex]

[tex]R_2 = 3.0 \Omega[/tex]

[tex]R_3 = 6.0 \Omega[/tex]

Substituting into the equation, we find

[tex]\frac{1}{R_T} = \frac{1}{4.0\Omega}+\frac{1}{3.0\Omega}+\frac{1}{6.0\Omega}=0.75\Omega^{-1}[/tex]

And so, the equivalent resistance is

[tex]R_T=\frac{1}{0.75 \Omega^{-1}}=1.33\Omega[/tex]

A simple machine can make work easier by reduce the amount of energy needed to perform a task, therefore, B. it magnifies the potential energy so that the kinetic energy is greater is the correct answer:)

This is a question that makes us REALLY want to know what "Which" means.

If you included a list of answer choices with your question, then the correct formula isn't on it.

The formula for converting temperature from degrees Celsius to degrees Fahrenheit is:

°F  =  1.8 · (°C) + 32

Explanation:

The two scales for measuring the temperature of an object are Celsius scale and Fahrenheit scale. Mathematically, it can be written as :

[tex]^{\circ} F=(\dfrac{9}{5}\times ^{\circ}C)+32[/tex]

Where

°F = degree Fahrenheit

°C = degree Celsius

For example, if T = 30°C. It can be converted to °F as :

[tex]^{\circ} F=(\dfrac{9}{5}\times 30)+32[/tex]

[tex]^{\circ} F=86[/tex]

So, 30°C is equal to 86 Fahrenheit. Hence, this is the required solution.

Answer:

[tex]1.88\cdot 10^{-5} A[/tex]

Explanation:

The capacitance of a parallel plate capacitor is given by:

[tex]C=\frac{\epsilon_0 A}{d}[/tex] (1)

where

[tex]\epsilon_0[/tex] is the vacuum permittivity

A is the area of the plates

d is the separation between the plates

The charge stored on the capacitor is given by

[tex]Q=CV[/tex] (2)

where C is the capacitance and V is the voltage across the capacitor.

The displacement current in the capacitor is given by

[tex]J=\frac{Q}{t}[/tex] (3)

where t is the time elapsed

Substituting (1) and (2) into (3), we find an expression for the displacement current:

[tex]J=\frac{CV}{t}=\frac{\epsilon_0 A}{d} \frac{V}{t}[/tex]

where we have

[tex]A=\pi (\frac{d}{2})^2=\pi (\frac{0.056 m}{2})^2=2.46\cdot 10^{-3} m^2[/tex]

[tex]d = 0.58 mm = 5.8\cdot 10^{-4} m[/tex]

[tex]\frac{V}{t}=500,000 V/s[/tex]

Substituting into the equation, we find

[tex]J=\frac{(8.85\cdot 10^{-12} F/m)(2.46\cdot 10^{-3} m^2)}{5.8\cdot 10^{-4}m}(500,000 V/s)=1.88\cdot 10^{-5} A[/tex]

The displacement current in the parallel-plate capacitor is approximately 0.024 A.

The displacement current in the capacitor can be calculated using the formula I = ε₀A(dV/dt), where ε₀ is the permittivity of free space, A is the area of the plates, and dV/dt is the rate of change of potential difference.

Given that the diameter of the capacitor is 5.6 cm, we can calculate the radius (r) by dividing the diameter by 2. The area (A) of the plates is then πr².

Plugging in the given values and solving for I, we get:

I = (8.85×10⁻¹² F/m)(π(0.028 m)²)(500,000 V/s)

I ≈ 0.024 A

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Answer:

Brain signals are converted

1.0m/s2 because net force and acceleration have a proprtional relationship

A) 89.5 m

The wavelength of a wave is given by:

[tex]\lambda=\frac{v}{f}[/tex]

where v is the wave speed and f the frequency. For the sound emitted by the whales,

[tex]f=17.0 Hz[/tex]

[tex]v=1521 m/s[/tex]

Therefore, the wavelength is

[tex]\lambda=\frac{1521 m/s}{17.0 Hz}=89.5 m[/tex]

B) 101.4 kHz

The speed of the sound emitted by the dolphins in the water is still

v = 1521 m/s

While the wavelength is

[tex]\lambda=1.50 cm=0.015 m[/tex]

So, re-arranging the previous equation we find the frequency:

[tex]f=\frac{v}{\lambda}=\frac{1521 m/s}{0.015 m}=101,400 Hz=101.4 kHz[/tex]

C) 1.31 cm

The frequency of the dog whistle is

f = 26.0 kHz = 26,000 Hz

While the speed of sound in air is

v = 340 m/s

Therefore, the wavelength is

[tex]\lambda=\frac{v}{f}=\frac{340 m/s}{26,000 Hz}=0.0131 m=1.31 cm[/tex]

D) 4.4 - 8.7 mm

The speed of the sound waves emitted by the bats in air is

v = 340 m/s

The minimum frequency is

f = 39.0 kHz = 39,000 Hz

So the corresponding wavelength is

[tex]\lambda=\frac{v}{f}=\frac{340 m/s}{39,000 Hz}=0.0087 m=8.7 mm[/tex]

The maximum frequency is

f = 78.0 kHz = 78,000 Hz

So the corresponding wavelength is

[tex]\lambda=\frac{v}{f}=\frac{340 m/s}{78,000 Hz}=0.0044 m=4.4 mm[/tex]

E) 6.2 MHz

The wavelength of the sound must be 1/4 the size of the tumor, so

[tex]\lambda=\frac{1}{4}(1.00 mm)=0.25 mm=2.5\cdot 10^{-4}m[/tex]

while the speed of sound across the tissue is

v = 1550 m/s

So the frequency must be

[tex]f=\frac{v}{\lambda}=\frac{1550 m/s}{2.5\cdot 10^{-4} m}=6.2\cdot 10^6 Hz=6.2 MHz[/tex]

Answer:

Both its velocity and acceleration is changing.

Explanation:

Before answering, we must remind that both velocity and acceleration are vectors, so they both consist of a magnitude and a direction.

We can easily answer the question by looking at the direction of the two vectors only. In a circular motion, in fact:

- The velocity is always tangential to the circular path --> this means that its direction changes at every instant, so velocity is not constant

- The acceleration always points towards the centre of the circular path --> this means that its direction changes at every instand, so acceleration is changing as well

The object moving in a circular path at a constant speed has a changing velocity due to the alteration in direction. Also, its acceleration is continuously changing, directed towards the center. So, both velocity and acceleration of the object are changing.

In this scenario, the object is moving in a circular path at a constant speed v. The term speed refers to the magnitude of velocity, which is a scalar quantity. Velocity, on the other hand, is a vector quantity including both magnitude (speed) and direction. Even if the speed is constant, the changing direction as the object moves along the circular path means the velocity of the object is continually changing.

The acceleration of the object is also non-zero and is directed towards the center of the circular path. This is known as centripetal or radial acceleration. Therefore, although the speed of the object remains constant, its velocity (due to changes in direction) and acceleration (towards the center) are continuously changing. Hence, the statement 'Both its velocity and acceleration are changing' is accurate.

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Curve of space time

Newton believed that time and space are absolute, while Einstein believed that the speed of light is absolute.

The net charge in the system is 0. All electrons that were sent to the rod are missing from the fur. Hence, the rod is a (-) while the fur is a (+).

Answer:

In order to satisfied the law of conservation of charge, If the rubber rod becomes negatively charged, then the fur becomes positively charged.

Explanation:

This law states that charge is neither created nor destroyed, it can only be transferred from one system to another. In this case the rubber rod obtains electrons from the fur, in consequence the rod, which was originally neutral becomes negatively charged (the number of electrons on it increase), and the fur which was originally neutral becomes positively charged (the number of electrons on it decrease).

Answer:

The electron will accelerate in the opposite direction of its motion.

Net Force = (mass) x (acceleration)  (Newton #2)

Net Force = (50 kg) x (6 m/s² down)

Net Force = (50 * 6) (kg-m/s² down)

Net Force = 300 Newtons down

A 50 kg skydiver is falling downwards and accelerating 6 m/s² down.  The net force on the skydiver is 300 N down.

A force is an effect that can alter an object's motion according to physics. An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.

Net Force = (50 kg) x (6 m/s² down)

Net Force = 300 kg-m/s² down

A 50 kg skydiver is falling downwards and accelerating 6 m/s² down.  The net force on the skydiver is 300 N down.

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Answer:

[tex]3.2\cdot 10^{-8} N[/tex]

Explanation:

The inital electrostatic force between the two spheres is given by:

[tex]F=k\frac{q_1 q_2}{r^2}[/tex]

where

[tex]F=8\cdot 10^{-9} N[/tex] is the initial force

k is the Coulomb's constant

q1 and q2 are the charges on the two spheres

r is the distance between the two spheres

The problem tells us that the two spheres are moved from a distance of r=20 cm to a distance of r'=10 cm. So we have

[tex]r'=\frac{r}{2}[/tex]

Therefore, the new electrostatic force will be

[tex]F'=k\frac{q_1 q_2}{(r')^2}=k\frac{q_1 q_2}{(r/2)^2}=4k\frac{q_1 q_2}{r^2}=4F[/tex]

So the force has increased by a factor 4. By using [tex]F=8\cdot 10^{-9} N[/tex], we find

[tex]F'=4(8\cdot 10^{-9} N)=3.2\cdot 10^{-8} N[/tex]

The force of attraction between the soheres when they are 10cm apart is 3.2 * 10^-8 N

This is the force pulling bodies together given by  

the force of attration, F = ( G q1 q2 ) / d^2

G refera to constant of attraction

q1 and q2 is the charges of the objects

d is the distance between the objects

G q1 q2 are all constant with respect to this question

let K = G * q1 * q2

F = k / d^2

for d = 20 cm = 0.2 m

F20 = k / 0.2^2

8*10^-9 = k / 0.2^2

K = 8*10^-9 *0.2^2

K = 3.2*10^-10

for d = 10 cm = 0.1 m

F10 = K / d^2

= (3.2*10^-10) * 0.1^2

= 3.2*10^-8 N

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body and surface waves is the answer

Answer:

4.4 kHz

Explanation:

The frequency of the beats is given by the frequency of the original ultrasound, [tex]f=41.2 kHz[/tex], and the frequency of the ultrasound reflected back from the car, [tex]f'[/tex]:

[tex]f_B = f'-f[/tex] (1)

The frequency of the reflected wave can be found by using the Doppler effect formula:

[tex]f'=\frac{v}{v-v_s}f[/tex]

where

v = 340 m/s is the speed of sound

[tex]v_s =33.0 m/s[/tex] is the speed of the car

[tex]f=41.2 kHz[/tex] is the frequency of the original sound

Substituting,

[tex]f'=\frac{340 m/s}{340 m/s-33.0 m/s}(41.2 kHz)=45.6 kHz[/tex]

So, the beat frequency (1) is

[tex]f_B = 45.6 kHz - 41.2 kHz=4.4 kHz[/tex]

The frequency of the beats is about 9.2 kHz

[tex]\texttt{ }[/tex]

Let's recall the Doppler Effect formula as follows:

[tex]\boxed {f' = \frac{v + v_o}{v - v_s} f}[/tex]

f' = observed frequency

f = actual frequency

v = speed of sound waves

v_o = velocity of the observer

v_s = velocity of the source

Let's tackle the problem!

[tex]\texttt{ }[/tex]

Given:

actual frequency = f = 41.2 kHz

velocity of the car = v_c = 33.0 m/s

speed of sound in air = v = 330 m/s

Asked:

frequency of the beats = Δf = ?

Solution:

Firstly , we will calculate the observed frequency by using the formula of Doppler Effect as follows:

[tex]f' = \frac{v + v_c}{v - v_c} \times f[/tex]

[tex]f' = \frac{330 + 33}{330 - 33} \times 41.2[/tex]

[tex]f' = \frac{363}{297} \times 41.2[/tex]

[tex]f' = \frac{11}{9} \times 41.2[/tex]

[tex]f' = 50 \frac{16}{45} \texttt{ kHz}[/tex]

[tex]f' \approx 50.4 \texttt{ kHz}[/tex]

[tex]\texttt{ }[/tex]

Next , we could calculate the frequency of the beats as follows:

[tex]\Delta f = f' - f[/tex]

[tex]\Delta f \approx 50.4 - 41.2[/tex]

[tex]\Delta f \approx 9.2 \texttt{ kHz}[/tex]

[tex]\texttt{ }[/tex]

The frequency of the beats is about 9.2 kHz

[tex]\texttt{ }[/tex]

[tex]\texttt{ }[/tex]

Grade: College

Subject: Physics

Chapter: Sound Waves

The correct answer is electrically charged.

When an object gains or loses electrons, it becomes electrically charged because it acquires an imbalance of positive and negative charges.

Explanation:

- Atoms are made up of positively charged protons in the nucleus and negatively charged electrons orbiting the nucleus.

- In a neutral atom, the number of protons and electrons are equal, resulting in an overall neutral charge.

- If an atom gains or loses electrons, it disrupts the balance of positive and negative charges, resulting in an electrically charged state.

- If an atom loses electrons, it becomes positively charged because it has more protons than electrons.

- If an atom gains electrons, it becomes negatively charged because it has more electrons than protons.

The other options are incorrect:

B) Electrically neutral: This option is incorrect because gaining or losing electrons causes an object to become electrically charged, not neutral.

C) Magnetically neutral: This option is incorrect because it refers to magnetic properties, not electric charges.

D) Magnetically polarized: This option is incorrect because it refers to magnetic properties, not electric charges.

Therefore, when an object gains or loses electrons, it becomes electrically charged due to the imbalance of positive and negative charges.

Complete question:

When an object gains or loses electrons, it becomes

A) electrically charged.

B) electrically neutral.

C) magnetically neutral.

D) magnetically polarized.

Water pipes burst because the water inside them expands is it gets close to freezing, and this causes an increase in pressure inside the pipe. When the pressure gets too high for the pipe to contain, it ruptures.

Water pipes can break in freezing weather when the water inside them expands and creates pressure. Different pipe materials have different coefficients of thermal expansion, affecting their susceptibility to breaking.

When water pipes freeze, the water inside them expands as it turns into ice. This expansion creates pressure on the walls of the pipe, which can cause it to crack or burst. The pressure is typically highest towards the closed faucet or valve, as the ice formation blocks water from flowing out.

The materials used to make the pipes also play a role in their susceptibility to breaking. Different materials have different coefficients of thermal expansion, which determines how much they expand or contract with temperature changes. Some materials, like Pyrex®, have a small coefficient of thermal expansion and are less likely to break.

It's important to note that freezing temperatures alone may not immediately cause the pipes to break. However, if the frozen water remains in the pipe for an extended period and the outside temperature remains cold, the expanding ice can eventually lead to pipe failure.

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When your in the mountains or in a quiet room

Answer:

Explained

Explanation:

The necessary condition for an echo to occur are

1) The distance between the sound source and the object of reflection must be equal to or greater than 17 meters.

2) the time period between hearing the original sound and the echo must not be less than 0.1 second, because human ear is not that sensitive to distinguish between two sounds within a gap of time less than 0.1 second.

1) Average velocity: 19 mi/h

The average velocity is given by:

[tex]v=\frac{d}{t}[/tex]

where

d is the displacement

t is the time taken

In this problem,

d = 3.8 mi is the displacement

[tex]t=12 min \cdot \frac{1}{60 min/h}=0.2 h[/tex] is the time taken

Substituting,

[tex]v=\frac{3.8 mi}{0.2 h}=19 mi/h[/tex]

Note that this is actually the average speed, not the average velocity, since there is no information about the direction of the motion.

2) [tex]10,309 mi/h^2[/tex]

The acceleration is given by

[tex]a=\frac{v-u}{t}[/tex]

where we have

v = 28 mph is the final velocity

u = 18 mph is the initial velocity

t = 3.5 s is the time taken

Conerting the time from seconds to hours,

[tex]t=3.5 s \cdot \frac{1}{3600 s/h}=9.7\cdot 10^{-4} h[/tex]

So the acceleration is

[tex]a=\frac{28 mph-18 mph}{9.7\cdot 10^{-4} h}=10,309 mi/h^2[/tex]

I believe it's hypoxia for your tissues and hypoxemia for your blood.

Answer:

Anemia

Explanation:

Edge 2021

Answer:b

Explanation:

A diverging lens always produces a virtual and upright image of an object placed in front of it.

To determine the correct statement among all the options, we need to know about the properties of the image formed by converging and diverging lens.

The image formed by a diverging lens is always erect (upright), virtual and diminished.

Thus we can conclude the statements (a) and (b) are correct.

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(a) -1.208 m

The position of the particle at time t is given by

[tex]x(t) = x_0 + v_0 t + \frac{1}{2}at^2[/tex]

where:

[tex]x_0 = 0.250 m[/tex] is the initial position

[tex]v_0 = 0.050 m/s[/tex] is the initial velocity

[tex]a=-0.240 m/s^2[/tex] is the acceleration

Substituting into the equation t=3.70 s, we find the position after 3.70 seconds:

[tex]x(3.70 s) = 0.250 m + (0.050 m/s)(3.70 s) + \frac{1}{2}(-0.240 m/s^2)(3.70 s)^2=-1.208 m[/tex]

(b) -0.838 m/s

The velocity of the particle at time t is given by:

[tex]v(t) = v_0 + at[/tex]

where

[tex]v_0 = 0.050 m/s[/tex] is the initial velocity

[tex]a=-0.240 m/s^2[/tex] is the acceleration

Substituting t = 3.70 s, we find the velocity after 3.70 seconds:

[tex]v(3.70 s) = 0.050 m/s + (-0.240 m/s^2)(3.70 s)=-0.838 m/s[/tex]

Answer:

A) They have the same kinetic energies, but different momenta.

Explanation:

Before answering, let's remind that:

- Kinetic energy is a scalar quantity, which is given by:

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

where m is the mass of the object and v is the speed.

- Momentum is a vector quantity, whose magnitude is given by:

[tex]p=mv[/tex]

where m is the mass of the object and v is the velocity, and whose direction is the same as the velocity.

By looking at the two definitions, we can say that:

- the two cars have same kinetic energy, because they have same mass and same speed

- The two cars have different momenta, because they do not have same velocity (in fact, their directions are different, since one is heading east and the other one is heading north)

The identical cars traveling at the same speed will have the same kinetic energies, but different momenta because momentum is a vector quantity dependent on direction.

The correct answer would be A) They have the same kinetic energies, but different momenta.

The two identical cars traveling at the same speed will have identical kinetic energies since kinetic energy depends only on mass and speed. The kinetic energy (KE) of an object can be calculated using the formula KE=1/2mv², where m is the mass and v is the speed of the object. Therefore, since the cars are identical and moving at the same speed, their kinetic energies will be the same.

However, their momenta will be different because momentum is a vector quantity, meaning direction matters. The formula for momentum is p=mv, where m is mass and v is velocity (speed in a given direction). Since one car is going east and the other is going north, their momenta are in different directions, hence, their momenta are different.

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Answer:

deflected toward bottom of the screen

Explanation:

When entering the region with magnetic field, a magnetic force is exerted on the proton. This force is perpendicular to both the direction of the magnetic field and the direction of the velocity of the proton.

The direction of the force can be determined by using the right-hand rule. We have:

- Index finger: direction of the velocity of the proton --> to the right

- Middle finger: direction of the magnetic field --> into the screen

- Thumb: direction of the magnetic force --> toward bottom of the screen

So, the correct answer is

deflected toward bottom of the screen

If no other forces act on the object, according to Newton’s first law, the spacecraft will continue moving at a constant velocity, assuming that a planet or something with large mass doesn’t cross its path. Forces are not required to continue the motion of an object on a frictionless plane at a constant rate.

If no other forces ever act on the spacecraft, it will continue moving at 32,500 mi/h in the same direction, because forces are not required for an object to continue its motion.

The spacecraft will  eventually curve away from a straight line, and its speed will change, as it comes within the gravitational influence of one or more of the objects out there in the Kuiper Belt and the Oort Cloud.

Answer:

0.017 m - 17 m

Explanation:

The relationship between wavelength and frequency of a wave is:

[tex]\lambda=\frac{v}{f}[/tex]

where v is the speed of the wave, [tex]\lambda[/tex] the wavelength and f the frequency.

The speed of sound waves in air at room temperature is

v = 340 m/s

For the lowest frequency, f = 20 Hz, the wavelength is

[tex]\lambda=\frac{340 m/s}{20 Hz}=17 m[/tex]

For the highest frequency, f = 20 kHz = 20,000 Hz, the wavelength is

[tex]\lambda=\frac{340 m/s}{20,000 Hz}=0.017 m[/tex]