Write any two differences between echo and reverberation.
Why the speed of sound in hot air is more than that in the cold air​

Answer:

The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.

Explanation:

hope it helps pls give me brainless

Answer:

[tex]0.629\ \text{rad/s}^2[/tex] counterclockwise

[tex]9.98\ \text{s}[/tex]

Explanation:

[tex]r_1[/tex] = Small drive wheel radius = 2.2 cm

[tex]\alpha_1[/tex] = Angular acceleration of the small drive wheel = [tex]8\ \text{rad/s}^2[/tex]

[tex]r_2[/tex] = Radius of pottery wheel = 28 cm

[tex]\alpha_2[/tex] = Angular acceleration of pottery wheel

As the linear acceleration of the system is conserved we have

[tex]r_1\alpha_1=r_2\alpha_2\\\Rightarrow \alpha_2=\dfrac{r_1\alpha_1}{r_2}\\\Rightarrow \alpha_2=\dfrac{2.2\times 8}{28}\\\Rightarrow \alpha_2=0.629\ \text{rad/s}^2[/tex]

The angular acceleration of the pottery wheel is [tex]0.629\ \text{rad/s}^2[/tex].

The rubber drive wheel is rotating in clockwise direction so the pottery wheel will rotate counterclockwise.

[tex]\omega_i[/tex] = Initial angular velocity = 0

[tex]\omega_f[/tex] = Final angular velocity = [tex]60\ \text{rpm}\times \dfrac{2\pi}{60}=6.28\ \text{rad/s}[/tex]

t = Time taken

From the kinematic equations of linear motion we have

[tex]\omega_f=\omega_i+\alpha_2t\\\Rightarrow t=\dfrac{\omega_f-\omega_i}{\alpha_2}\\\Rightarrow t=\dfrac{6.28-0}{0.629}\\\Rightarrow t=9.98\ \text{s}[/tex]

The time it takes the pottery wheel to reach the required speed is [tex]9.98\ \text{s}[/tex]

for sure thermometers and pryometers as I just learned and did some search ing. so these are. two classes of the heat measure measurement s! your welcomes!!

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a centrifugal clutch works, as the name suggests, through centrifugal force. ... The rotation of the hub forces the shoes or flyweights outwards until they come into contact with the clutch drum, the friction material transmits the torque from the flyweights to the drum. The drive is then connected

Answer:

1. Rₑq = 4 Ω

2. R₂ = 6 Ω

3. Vₜ = 12 V, V₁ = 12 V, V₂ = 12 V

4. Iₜ = 3 A, I₁ = 1 A, I₂ = 2 A

Explanation:

1. Determination of the equivalent resistance

Voltage (V) = 12 V

Current (I) = 3 A

Resistance (Rₑq) =?

V= IRₑq

12 = 3 × Rₑq

Divide both side by 3

Rₑq = 12 / 3

Rₑq = 4 Ω

Thus, the equivalent resistance (Rₑq) = 4 Ω

2. Determination of R₂.

Equivalent resistance (Rₑq) = 4 Ω

Resistance 1 (R₁) = 12 Ω

Resistance 2 (R₂)

Since the resistor are in parallel arrangement, the value of R₂ can be obtained as follow:

Rₑq = R₁ × R₂ / R₁ + R₂

4 = 12 × R₂ / 12 + R₂

Cross multiply

4(12 + R₂) = 12R₂

48 + 4R₂ = 12R₂

Collect like terms

48 = 12R₂ – 4R₂

48 = 8R₂

Divide both side by 8

R₂ = 48 / 8

R₂ = 6 Ω

3. Determination of the total voltage (Vₜ), V₁ and V₂.

From the question given above, the total voltage is 12 V

Since the resistors are arranged in parallel connection, the same voltage will go through them.

Thus,

Vₜ = V₁ = V₂ = 12 V

4. Determination of the total current (Iₜ), I₁ and I₂

From the question given above, the total current (Iₜ) is 3 A

Next, we shall determine I₁. Since the resistors are arranged in parallel connection, different current will pass through each resistor respective.

Vₜ = V₁ = 12 V

R₁ = 12 Ω

I₁ =?

V₁ = I₁R₁

12 = I₁ ×12

Divide both side by 12

I₁ = 12 / 12

I₁ = 1 A

Next, we shall determine I₂. This can be obtained as follow:

Iₜ = 3 A

I₁ = 1 A

I₂ =?

Iₜ = I₁ + I₂

3 = 1 + I₂

Collect like terms

I₂ = 3 – 1

I₂ = 2 A

Answer:

19.9 N/m

Explanation:

From the question,

Applying Hook's law

F = Ke.................. Equation 1

Where F = Force on the spring, k = spring constant, e = extension

But the force on the spring is the weight of the mass

Therefore,

mg = ke.................. Equation 2

Where m = mass. g = acceleration due to gravity

make e the subject of the equation

e = mg/e................ Equation 3

Given: m = 455 g = 0.455 kg, e = 22.4 cm = 0.224 m,

Constant: g = 9.8 m/s²

Substitute these values into equation 3

e = (0.455×9.8)/0.224

e = 19.9 N/m

The spring constant of the given spring is 20 N/m.

The given parameters:

The spring constant is calculated by applying Hooke's law as follows;

[tex]F = kx\\\\mg = kx\\\\k = \frac{mg}{x} \\\\k = \frac{0.455 \times 9.8}{0.224} \\\\k = 20 \ N/m[/tex]

Thus, the spring constant of the spring is 20 N/m.

Learn more about Hooke's law here: https://brainly.com/question/2648431

Answer:

Drink water

Make your find fresh by doing the stuff you love too ❤️

Answer:

correct answer is C

Explanation:

In this exercise, you are asked to complete the sentences so that the sentence makes sense.

1) in projectile launching, the only force that acts is gravity in the vertical direction, so the time of going up is EQUAL to the time of going down

correct answer C

2) when a body falls freely, the acceleration is the ratio of gravity, therefore if it starts from rest, its height is

            y = v₀ t - ½ gt²

v₀ = 0

             y = -1/2 g t²

so the position is not proportional to the square of the time

correct answer is C

Less than R, less than 2R, less than 3R, and less than any other possible hookup of any one,  any two, or all three of these resistors.

Answer:

D. the net heat flow is zero

Explanation:

In one cycle of any heat engine, three things happen:

[tex]Q_H = W + Q_C[/tex]

Conclusively, the net heat flow is zero

Answer:

2) twice the amplitude and half the wavelength

Explanation:

The diagram below represent that the waves A and B in the same medium should be option b where the amplitude is to be twice and the wavelength should be half.

Amplitude in terms of physics that represent the maximum displacement or the distance that should be moved via the point  with respect to the vibrating body or the wave that should be determined from the equilibrium position.

Also, it should be equivalent to the one half the vibration path length.

Therefore, the option b is correct.

Learn more about wavelength here: https://brainly.com/question/19587294

Answer:

the stopping distance is greater than the free length of the track, the vehicle leaves the track before it can brake

Explanation:

This problem can be solved using the kinematics relations, let's start by finding the final velocity of the acceleration period

          v² = v₀² + 2 a₁ x

indicate that the initial velocity is zero

          v² = 2 a₁ x

let's calculate

          v = [tex]\sqrt {2 \ 15.0 \ 645}[/tex]

          v = 143.666 m / s

now for the second interval let's find the distance it takes to stop

          v₂² = v² - 2 a₂ x₂

in this part the final velocity is zero (v₂ = 0)

         0 = v² - 2 a₂ x₂

         x₂ = v² / 2a₂

let's calculate

         x₂ = [tex]\frac{ 143.666^2 }{2 \ 18.2}[/tex]

         x₂ = 573 m

as the stopping distance is greater than the free length of the track, the vehicle leaves the track before it can brake

Answer:

a) 2250 J

b) 0 J

c) 2250 J

Explanation:

a) Since, the process is isochoric

the change in internal energy

[tex]\Delta U = n C_v(T_f-T_i)[/tex]

Here, n = 0.2 moles

Cv = 12.5 J/mole.K

We have to find T_f so we can use gas equation as

[tex]\frac{P_1V_1}{P_2V_2} =\frac{T_i}{T_f}\\Since, V_1=V_2 [isochoric/process]\\\Rightarrow \frac{P_{atm}}{4P_{atm}} = \frac{300}{T_f} \\\Rightarrow T_f = 1200 K[/tex]

So,  [tex]\Delta U= 0.2\times12.5(1200-300)\\=2250 J[/tex]

b) Since, the process is isochoric no work shall be done.

c) By first law of thermodynamics we have

[tex]\Delta U = Q-W\\Since, W = 0\\\Delta U = Q\\Therefore, Q = 2250 J[/tex]

Since, Q is positive 2250 J of heat will flow into the system.

Answer:

A. I = V / R = 12 / 252 = .048 amps

V = I * R = .048 * 252 = 12 V

V is also the reading the voltage across the battery (12 Volts)

Answer:

i think is c

Explanation:

Answer:

C

Explanation:

C makes more sense than D, Because it says the minimum value is when it stays at rest.

Answer:

Every mass

Explanation:

Because Force of gravity always act toward the center of the earth , so when an object is thrown up ,the force of gravity will act in opposite direction of motion ,that's toward the center of earth. The force is towards the center of the Earth (more or less). which gives it time get touch every mass.

The gravitational force of attraction exists between every objects in the universe that are having mass. So, the correct option is A.

Force of gravity is defined as the force of attraction experienced by bodies due to the gravitational field of earth.

Here,

The gravitational force is the attractive force experienced by any body that have mass. Gravity is an attractive force such that every bodies that are having mass in the earth are being attracted towards the centre of earth.

The equation of gravitational force is given by,

F = GMm/r²

where G is the gravitational constant of earth, M is the mass of earth and m is the mass of the body which is being attracted towards earth's centre, and r is the distance between earth and the body.

From the equation, it is shown that gravitational force is proportional to the masses. More the mass of the objects, more will be the gravitational force of attraction existing between them.

Hence,

The gravitational force of attraction exists between every objects in the universe that are having mass.

To learn more about force of gravity, click:

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Explanation:

From Faraday's law,

[tex]e m f &=-\frac{d \phi}{d t} \\ &=-\frac{d}{d t}(B A \cos \theta) \\ &=-\frac{d}{d t}(B l h \cos \theta) \\ &=-B l \cos \theta \frac{d h}{d t} \\ &=-B l v \cos 0^{\circ} \\ &=-B l v[/tex]

Here, B is the magnetic field, l is the length of the rod, and v is the velocity of the rod.

 [tex]e m f &=-B l(\sqrt{2 g h}) \\ 9.2 \times 10^{-4} \mathrm{~V} &=-B(0.90 \mathrm{~m})\left(\sqrt{2\left(9.8 \mathrm{~m} / \mathrm{s}^{2}\right)(32 \mathrm{~m})}\right) \\ B &=\frac{9.2 \times 10^{-4} \mathrm{~V}}{(0.90 \mathrm{~m})\left(\sqrt{2\left(9.8 \mathrm{~m} / \mathrm{s}^{2}\right)(32 \mathrm{~m})}\right)} \\ &=0.408 \times 10^{-4} \mathrm{~T}[/tex]

Answer:

if you have a rotating electric current it will create a magnetic field on earth flowing of liquid metal in the outer core of the planets General Health recurrence the rotation of earth on its Axis causes this electric current to form a magnetic field which extends around the planet.

Explanation:. please give me brainlest

Answer:

C

Explanation:

if you measure your body's flexibility then you can keep track of how flexible you have gotten over time

Explanation:

When there is a high frequency sound the speed of the vibrations is faster and makes a high pitch sound. When there is a low frequency sound the speed of the vibrations is slower and makes a lower pitch sound.

Answer:

The formula is dimensionally correct.

Explanation:

Given

[tex]s = ut + \frac{1}{2}at^2[/tex]

Required

Prove its correctness

Write out the dimension of each:

[tex]s = M^0LT^0[/tex] --- displacement

[tex]ut = M^0LT^{-1} * T[/tex] --- velocity * time

[tex]\frac{1}{2}at^2 = M^0LT^{-2} * T^2[/tex] --- acceleration * square of time

The expression becomes:

[tex]s = ut + \frac{1}{2}at^2[/tex]

[tex]M^0LT^0 = M^0LT^{-1} * T + M^0LT^{-2} * T^2[/tex]

Apply law of indices

[tex]M^0LT^0 = M^0LT^{-1+1} + M^0LT^{-2+2}[/tex]

[tex]M^0LT^0 = M^0LT^{0} + M^0LT^{0}[/tex]

[tex]M^0LT^0 = M^0LT^{0}[/tex]

Both sides of the equation are equal

Answer:

1.) 10.61 A

2.) 0.27 A

Explanation:

Given that a sinusoidal A.C has a maximum value of 15A.

1) What are its r.m.s values?

ii) If the time is recorded from the instant the current is zero and is becoming

positive, what is the instantaneous value of the current after 1/300s, given the

frequency is 50 Hz.​

Solution.

1.)

The r.m.s current = peak current/root 2

The r.m.s current = 0.7071 × 15

The r.m.s current = 10.61 A

2.)

Given that

Time = 1/300 s

Frequency = 50 Hz

Instantaneous current can be calculated by using the formula

I = I sin wt

Where w = 2πf

Instantaneous current = 15( sin 2πft)

I = 15 × sin ( 2 × 3.143 × 50 × 1/300 )

I = 15 × sin ( 1.047 )

I = 15 × 0.01827

I = 0.27 A

Therefore, the instantaneous current is 0.27A

Answer:

a)    I= I₀ (cos²θ - cos⁴θ)    b) 75.5º

Explanation:

a) For this exercise we must use Malus's law

         I = I₀ cos² θ

where tea is the angle between the two polarizers.

We apply this expression to our case

* Polarizer 1 suppose that it is vertical and polarizer 2 (intermediate) is at an angle θ with respect to the vertical

         I₁ = I₀ cos² θ

* We analyze for the polarity 2 and the last polarizer 3 which indicate that it must be at 90º from the first one, therefore it must be horizontal.

The angle of polarizers 2 and 3 is θ' measured from the horizontal, if we measure with respect to the vertical

              θ₂ = 90- θ’ = θ

fiate that in the exercise we must take a reference system and measure everything with respect to this system.

          I = I₁ cos² θ'

we substitute

         I = (I₀ cos² tea) cos² (θ - 90)

        cos (θ -90) = cos θ cos 90 + sin θ sin 90 = sin θ

         I = Io cos² θ sin² θ

        1= cos²θ+ sin²θ

       sin²θ = 1 - cos²θ

        I= I₀ (cos²θ - cos⁴θ)

b) to find when the intensity is maximum,

we can use that we have an extreme point when the drift is zero

          [tex]\frac{dI}{d \theta}[/tex] = 0

          \frac{dI}{d \theta}= Io (2 cos θ - 4 cos³θ) = 0

whereby

            cos θ - 2 cos³ θ = 0

            cos θ ( 1 - 2 cos² θ) = 0  

The zeros of this function are in

           θ = 90º

           1-2cos²θ =0       cos θ = 0.25  θ =  75.5º

Let's analyze this two results for the angle of 90º the intnesidd is zero with respect to the first polarizer, so it is not an acceptable solution.

Consequently, the angle that allows the maximum intensity to pass is 75.5º

Answer:

True

Explanation:

Given that Power whose unit is Watt equates to one joule of work per second. It implies that Power is directly proportional to the work done and inversely proportional to the time to do the work.

Therefore, in this case, the right answer to the question is that it is TRUE that the power is inversely proportional with time

Answer:

The first answer is correct.  All of the other options include sound, which travels by material force, and can not be transmitted in a vacuum.  Infra-red, radio, and microwaves are all different frequencies of light, and can thus travel through a vacuum.

Answer:

406850000 J

Explanation:

From the question

Q = cm...................... Equation 1

Where Q = Amount of heat, c = latent heat of water, m = mass of water

Given: c = 813700 J/g, m = 500 grams

Substitute these values into equation 1

Q = 500×813700

Q = 406850000 J

Hence the amount of heat requires to boil water at 100°C = 406850000 J

Answer:

   v₀ = 60.38 mi / h

With this stopping distance, the starting speed should have been 60.38 mi/h, which is much higher than the maximum speed allowed.

Explanation:

For this exercise let's start by using Newton's second law

Y axis

        N-W = 0

        N = W

X axis

         fr = m a

the expression for the friction force is

         fr = μ N

we substitute

        μ mg = m a

        μ g = a

calculate us

         a = 0.620  9.8

         a = 6.076 m / s²

now we can use the kinematics relations

          v² = v₀² - 2 a x

suppose v = 0

          v₀ = [tex]\sqrt{2ax}[/tex]Ra 2ax

let's calculate

         v₀ = [tex]\sqrt{2 \ 6076 \ 60}[/tex]

         v₀ = 27.00 m / s

let's slow down to the english system

          v₀ = 27.0 m / s (3.28 ft / 1m) (1 mile / 5280 ft) (3600s / 1h)

          v₀ = 60.38 mi / h

With this stopping distance, the starting speed should have been 60.38 mi/h, which is much higher than the maximum speed allowed.

Answer:

The sum of an object's potential and kinetic energies is called the object's mechanical energy. As an object falls its potential energy decreases, while its kinetic energy increases. The decrease in potential energy is exactly equal to the increase in kinetic energy.

Explanation:

Answer:

the potential decrease and kinetic increase

Explanation:

because it goes from a state of rest to a state of movement

cold, dry, and stable air masses .