A sound wave in a steel rail has a frequency of 620 hz and a wavelength of 10.5m. What is the speed of sound in steel?

Answer:

a) The initial total mechanical energy of the projectile is 498556.296 joules.

b) The work done on the projectile by air friction is 125960.4 joules.

c) The speed of the projectile immediately before it hits the ground is approximately 82.475 meters per second.

Explanation:

a) The system Earth-projectile is represented by the Principle of Energy Conservation, the initial total mechanical energy ([tex]E[/tex]) of the project is equal to the sum of gravitational potential energy ([tex]U_{g}[/tex]) and translational kinetic energy ([tex]K[/tex]), all measured in joules:

[tex]E = U_{g} + K[/tex] (Eq. 1)

We expand this expression by using the definitions of gravitational potential energy and translational kinetic energy:

[tex]E = m\cdot g\cdot y + \frac{1}{2}\cdot m\cdot v^{2}[/tex] (Eq. 1b)

Where:

[tex]m[/tex] - Mass of the projectile, measured in kilograms.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]y[/tex] - Initial height of the projectile above ground, measured in meters.

[tex]v[/tex] - Initial speed of the projectile, measured in meters per second.

If we know that [tex]m = 54\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]y = 132\,m[/tex] and [tex]v = 126\,\frac{m}{s}[/tex], the initial mechanical energy of the earth-projectile system is:

[tex]E = (54\,kg)\cdot \left(9.807\,\frac{m}{s^{2}}\right)\cdot (132\,m)+\frac{1}{2}\cdot (54\,kg)\cdot \left(126\,\frac{m}{s} \right)^{2}[/tex]

[tex]E = 498556.296\,J[/tex]

The initial total mechanical energy of the projectile is 498556.296 joules.

b) According to this statement, air friction diminishes the total mechanical energy of the projectile by the Work-Energy Theorem. That is:

[tex]W_{loss} = E_{o}-E_{1}[/tex] (Eq. 2)

Where:

[tex]E_{o}[/tex] - Initial total mechanical energy, measured in joules.

[tex]E_{1}[/tex] - FInal total mechanical energy, measured in joules.

[tex]W_{loss}[/tex] - Work losses due to air friction, measured in joules.

We expand this expression by using the definitions of gravitational potential energy and translational kinetic energy:

[tex]W_{loss} = E_{o}-K_{1}-U_{g,1}[/tex]

[tex]W_{loss} = E_{o} -\frac{1}{2}\cdot m\cdot v_{1}^{2}-m\cdot g\cdot y_{1}[/tex] (Eq. 2b)

Where:

[tex]m[/tex] - Mass of the projectile, measured in kilograms.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]y_{1}[/tex] - Maximum height of the projectile above ground, measured in meters.

[tex]v_{1}[/tex] - Current speed of the projectile, measured in meters per second.

If we know that [tex]E_{o} = 498556.296\,J[/tex], [tex]m = 54\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]y_{1} = 297\,m[/tex] and [tex]v_{1} = 89.3\,\frac{m}{s}[/tex], the work losses due to air friction are:

[tex]W_{loss} = 498556.296\,J -\frac{1}{2}\cdot (54\,kg)\cdot \left(89.3\,\frac{m}{s} \right)^{2} -(54\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (297\,m)[/tex]

[tex]W_{loss} = 125960.4\,J[/tex]

The work done on the projectile by air friction is 125960.4 joules.

c) From the Principle of Energy Conservation and Work-Energy Theorem, we construct the following model to calculate speed of the projectile before it hits the ground:

[tex]E_{1} = U_{g,2}+K_{2}+1.5\cdot W_{loss}[/tex] (Eq. 3)

[tex]K_{2} = E_{1}-U_{g,2}-1.5\cdot W_{loss}[/tex]

Where:

[tex]E_{1}[/tex] - Total mechanical energy of the projectile at maximum height, measured in joules.

[tex]U_{g,2}[/tex] - Potential gravitational energy of the projectile, measured in joules.

[tex]K_{2}[/tex] - Kinetic energy of the projectile, measured in joules.

[tex]W_{loss}[/tex] - Work losses due to air friction during the upward movement, measured in joules.

We expand this expression by using the definitions of gravitational potential energy and translational kinetic energy:

[tex]\frac{1}{2}\cdot m \cdot v_{2}^{2} = E_{1}-m\cdot g\cdot y_{2}-1.5\cdot W_{loss}[/tex] (Eq. 3b)

[tex]m\cdot v_{2}^{2} = 2\cdot E_{1}-2\cdot m \cdot g \cdot y_{2}-3\cdot W_{loss}[/tex]

[tex]v_{2}^{2} = 2\cdot \frac{E_{1}}{m}-2\cdot g\cdot y_{2}-3\cdot \frac{W_{loss}}{m}[/tex]

[tex]v_{2} = \sqrt{2\cdot \frac{E_{1}}{m}-2\cdot g\cdot y_{2}-3\cdot \frac{W_{loss}}{m} }[/tex]

If we know that [tex]E_{1} = 372595.896\,J[/tex], [tex]m = 54\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]y_{2} =0\,m[/tex] and [tex]W_{loss} = 125960.4\,J[/tex], the final speed of the projectile is:

[tex]v_{2} =\sqrt{2\cdot \left(\frac{372595.896\,J}{54\,kg}\right)-2\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (0\,m)-3\cdot \left(\frac{125960.4\,J}{54\,kg}\right) }[/tex]

[tex]v_{2} \approx 82.475\,\frac{m}{s}[/tex]

The speed of the projectile immediately before it hits the ground is approximately 82.475 meters per second.

Explanation:

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Answer: sorry here’s the answers, I didn’t feel like typing it all

Explanation:

The correct answer to the 5 questions are;

1) Option A; The current stays the same throughout the circuit.

2) Option A;  The current will stay the same at 1 amp after passing through both resistors.

3) Option C; R1: 12 V, R2: 12 V

4) Option A; I1 is equal to I2

5) Option C; The sum of the current flowing in is equal to the sum of current flowing out.

1) In an electrical circuit, usually as current moves through each component, it stays the same. Thus, option A is correct.

2) Formula for current is;

I = V/R

We are told that there are two resistors in series each having a resistance of 5Ω. Thus; Total resistance = 5 + 5 = 10 Ω.

Thus; Current = 10/10 = 1 A.

The current will stay same at 1 A after passing through both resistors.

3) From the circuit we are given, we see that the Voltage is 12 V. Now, the same voltage would be transmitted through both resistor R1 and R2.

Option C is correct

4) The current splits upon passing resistor 1 and as such it means the current I2 going through the second resistor would be the same. Thus; I1 = I2.

5) Kirchoff's junction rule states that all the incoming currents to a particular junction must be equal to sum of all currents going out of that same junction. Thus, option C is correct.

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Answer:

The amount of heat required is [tex]H_t = 1.37 *10^{6} \ J [/tex]

Explanation:

From the question we are told that

The mass of water is [tex]m_w = 20 \ ounce = 20 * 28.3495 = 5.7 *10^2 g[/tex]

The temperature of the water before drinking is [tex]T_w = 3.8 ^oC[/tex]

The temperature of the body is [tex]T_b = 36.6^oC[/tex]

Generally the amount of heat required to move the water from its former temperature to the body temperature is

[tex]H= m_w * c_w * \Delta T[/tex]

Here [tex]c_w [/tex] is the specific heat of water with value [tex]c_w = 4.18 J/g^oC [/tex]

So

[tex]H= 5.7 *10^2 * 4.18 * (36.6 - 3.8)[/tex]

=> [tex]H= 7.8 *10^{4} \ J [/tex]

Generally the no of mole of sweat present mass of water is

[tex]n = \frac{m_w}{Z_s}[/tex]

Here [tex]Z_w[/tex] is the molar mass of sweat with value

[tex]Z_w = 18.015 g/mol[/tex]

=> [tex]n = \frac{5.7 *10^2}{18.015}[/tex]

=> [tex]n = 31.6 \ moles [/tex]

Generally the heat required to vaporize the number of moles of the sweat is mathematically represented as

[tex]H_v = n * L_v[/tex]

Here [tex]L_v[/tex] is the latent heat of vaporization with value [tex]L_v = 7 *10^{3} J/mol[/tex]

=> [tex]H_v = 31.6 * 7 *10^{3} [/tex]

=> [tex]H_v = 1.29 *10^{6} \ J [/tex]

Generally the overall amount of heat energy required is

[tex]H_t = H + H_v[/tex]

=> [tex]H_t = 7.8 *10^{4} + 1.29 *10^{6}[/tex]

=> [tex]H_t = 1.37 *10^{6} \ J [/tex]

We are given:

F = 300N

acceleration (a) = 0.750 m/s²

Solving for the mass of the object:

We know from the second equation of motion:

F = ma

replacing the variables

300 = m * 0.75

m = 300 * 100/ 75

m = 300 * 4/3

m = 100 * 4

m = 400 kg

Answer

No dan should reduce his discretionary apendings.

Explanation:

The SPEED of a car on the highway is 75 mph.

(You're correct on #6.)

Answer:

sound water because sound is the most important electronic wave for water

Answer:

energy

Explanation:

Energy can't be destroyed or created, just transferred.

Answer:

Newton's first law says that if the net force on an object is zero ( Σ F = 0 \Sigma F=0 ΣF=0\Sigma, F, equals, 0), then that object will have zero acceleration. That doesn't necessarily mean the object is at rest, but it means that the velocity is constant.

Explanation:

According to Newton’s first law of motion, a moving object acted on by a net force of zero will continue in motion.

Newton's first law of motion states that an object in state of rest or uniform motion in a straight line will continue in that state unless it is acted upon by an external force.

This first is also known as the law of inertia because it is the reluctance of an object in motion to stop moving or reluctance of an object at rest to start moving which depends on the mass of the object.

Thus, we can conclude that according to Newton’s first law of motion, a moving object acted on by a net force of zero will continue in motion.

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630 kilometers for the whole journey

Answer:

c-) both objects will reach the bottom at the same instant.

(b) decrease.

Explanation:

Although the feather is lighter than the coin, the tube where the experiment is performed is evacuated. Therefore there is no air that prevents the feather from falling freely with the same acceleration and speed as the coin.

In fact in the equations of kinematics proposed by Newton, the mass of the bodies is not taken into account, as we can see in the following equation:

[tex]v_{f}= v_{i} +g*t[/tex]

where:

Vf = final velocity [m/s]

Vi = initial velocity [m/s]

g = gravity acceleration [m/s^2]

t = time [s]

Therefore the answer is C.

Gravitational pull is a function of height, as the height of the body increases, the force of gravity decreases.

Answer:

2.5

Explanation:

Answer:

motion repeating itself is referred to as periodic or oscillatory motion. An object in such motion oscillates about an equilibrium position due to a restoring force or torque. ... This motion is important to study many phenomena including electromagnetic waves, alternating current circuits, and molecules.

Explanation:

Answer:

Moves to and from about it's mean position in a fixed time interval.

Complete Question

The complete question is shown on the first uploaded image

Answer:

1

  A

2

A

Explanation:

From the question the data given for Error (mV) is -15

-15.17

8.67

-13.74

-20.69

-6.96

-1.36

-2.96

-9.26

3.11

-14.12

6.39

-14.77

Generally

The null hypothesis is [tex]H_o : \mu = 0[/tex]

The alternative hypothesis is [tex]H_a : \mu \ne 0[/tex]

The sample size is n = 13

Here [tex]\mu[/tex] represents the true error bias (i.e population error bias)

Generally the sample error bias is mathematically represented as

[tex]\= x = \frac{ \sum x_i}{n}[/tex]

=> [tex]\= x = \frac{ -15.17 + 8.67 + (-13.74) + \cdots + (-14.77) }{13}[/tex]

[tex]\= x = -7.37[/tex]

Generally the standard deviation is mathematically represented as

[tex]\sigma = \sqrt{\frac{\sum (x_i - \= x )^2}{n} }[/tex]

=> [tex]\sigma = \sqrt{\frac{ (-15.17-( -7.37) )^2 + (8.67 -( -7.37) )^2 + \cdots + (-14.77 -( -7.37) )^2 }{13} }[/tex]

=> [tex]\sigma = \sqrt{ 119.385}[/tex]

=> [tex]\sigma = 10.926[/tex]

Generally the test statistics is mathematically represented as

[tex]t = \frac{\= x - \mu }{\frac{\sigma }{\sqrt{n} } }[/tex]

=> [tex]t = \frac{ -7.37 - 0 }{\frac{10.926}{\sqrt{13} } }[/tex]

=> [tex]t = -2.838[/tex]

Generally the p-value is mathematically represented as

[tex]p-value = 2 P(t < -2.432)[/tex]

From the z-table  [tex]P(t < -2.432) =  0.0075 [/tex]

So  [tex]p-value  =  2* 0.0075 [/tex]

=>  [tex]p-value  = 0.015 [/tex]

So given that  p-value is  less than the [tex] \alpha = 0.05[/tex] then we reject the null hypothesis and conclude that the oscilloscope has an error bias

Answer: Temperature

Explanation:

The average kinetic energy of the particles in a gas is proportional to the temperature of the gas. Because the mass of these particles is constant, the particles must move faster as the gas becomes warmer.

"The kinetic energy of an object is the energy that it possesses due to its motion."

"The product of the half of the mass of each gas molecule and the square of RMS speed."

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Answer:

oh I know that sounds good to me

Which of the following statements describes how a balance obtains a measurement ​

Explanation:

A balance obtains a measurement by the sides of an object which are measured and multiplied to get the final measurement. Thus, the correct option is C.

A balance is an instrument used for comparing the weights of two objects. It is usually for the scientific purposes, to determine the difference in mass or weight of an object.

Weighing of objects directly requires that the balance be carefully zeroed that is it reads zero with nothing on the balance pan in order to obtain accurate results of the measurement.

The sides of an object are measured and multiplied with a factor to get the final measurement of the object. Through this, a balance obtains the measurement.

Therefore, the correct option is C.

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Answer:

It would take 5 seconds

Explanation:

I can't find the 'delta' sign nor the vector sign so just pretend that displacement, time and velocity has them.

V = d / t

34 = 170 / t

34 x t = 170

34t = 170

t = 170 / 34

t = 5

Answer:

v = 190 m/s

Explanation:

Given that,

Initial velocity of a car, u = 10 m/s

Distance, d = 500 m

Time, t = 5 s

We need to find the final velocity of the car. Firstly we can find the acceleration of the car using second equation of motion as follows :

[tex]d=ut+\dfrac{1}{2}at^2\\\\500=10\times 5+\dfrac{a}{2}\times 5^2\\\\500=50+\dfrac{25a}{2}\\\\450=\dfrac{25a}{2}\\\\a=\dfrac{450\times 2}{25}\\\\a=36\ m/s^2[/tex]

let v is the final velocity. using First equation of motion to find a as follows :

v=u+at

v=10+36(5)

v=190 m/s

So, the final velocity of the car is 190 m/s.

Answer:

Vy = 80.5 [m/s]

Explanation:

In order to solve this problem we must use the Pythagorean theorem.

V = 90 [m/s]

The components are Vx and Vy:

Therefore:

[tex]v=\sqrt{v_{x}^{2} + v_{y}^{2} }[/tex]

where:

Vy = 2*Vx ; because one is twice of the other.

[tex]90 = \sqrt{v_{x}^{2} +(2*v_{x})^{2} }\\ 90 =\sqrt{v_{x}^{2}+4*v_{x}^{2}} \\90 =\sqrt{5v_{x}^{2}} \\90=2.23*v_{x} \\v_{x}=40.25[m/s][/tex]

and the bigger vector is:

Vy = 40.25*2

Vy = 80.5 [m/s]

Given parameters:

Mass of puck = 162g  = 0.162kg (1000g = 1kg)

Force exerted on puck = 171N

Final velocity  = 42.3m/s

Unknown

A.  time of the acceleration

B. radius of the curve?

Solution:

A. time of the acceleration

the initial velocity of the puck = 0m/s

    We know that;

              Force  = mass x acceleration

      Acceleration  = [tex]\frac{Final velocity - Initial velocity}{time taken}[/tex]

       Acceleration  = [tex]\frac{42.3 - 0}{t}[/tex]

  So force  = mass x [tex]\frac{42.3 }{t}[/tex]

 Input the parameters and solve for time;

             171 = 0.162 x [tex]\frac{42.3 }{t}[/tex]

             171 = [tex]\frac{6.85}{t}[/tex]  

                 t = [tex]\frac{6.85}{171}[/tex]   = 0.04s

The time of acceleration is 0.04s

B. radius of the curve;

      to solve this, we apply the centripetal force formula;

               F  = [tex]\frac{mv^{2} }{r}[/tex]

  where;

      F is the centripetal force

     m is the mass

      v is the velocity

      r is the radius

               Since the force exerted on the puck is 151;

      input the parameters and solve for r²;

             151 = [tex]\frac{0.162 x 42.3^{2} }{r}[/tex]

               151r  = 0.162 x 42.3²

                r  = 1.92m

The radius of the circular curve is 1.92m

Answer:

a) Time it will taken for the column surface temperature to rise to 27°C is  

17.1 hours

b) Amount of heat transfer is 5320 kJ  

c) Amount of heat transfer until the surface temperature reaches 27°C is 4660 kJ

Explanation:

Given that;

Diameter D = 30 cm

Height H = 4m

heat transfer coeff h = 14 W/m².°C

thermal conductivity k = 0.79 W/m.°C

thermal diffusivity α  = 5.94 × 10⁻⁷ m²/s

Density p = 1600 kh/m³

specific heat Cp = 0.84 Kj/kg.°C

a)

the Biot number is

Bi = hr₀ / k

we substitute

Bi = (14 W/m².°C × 0.15m) / 0.79 W/m.°C

Bi = 2.658

From the coefficient for one term approximate of transient one dimensional heat conduction The constants λ₁ and A₁ corresponding to this Biot number are,  

λ₁ = 1.7240

A₁ = 1.3915

Once the constant J₀ = 0.3841 is determined from corresponding to the constant λ₁

the Fourier number is determined to be  

[ T(r₀, t) -T∞ ] / [ Ti - T∞]  = A₁e^(-λ₁²t') J₀ (λ₁r₀ / r₀)

(27 - 28) / (14 - 28)   = (1.3915)e^-(17240)²t (0.3841)  

t' = 0.6771

Which is above the value of 0.2. Therefore, the one-term approximate solution (or the transient temperature charts) can be used. Then the time it will take for the column surface temperature to rise to 27°C becomes  

t =  t'r₀² / ₐ

= (0.6771 × 0.15 m)² /  (5.94 x 10⁻⁷ m²/s)

= 23,650 s

= 7.1 hours

Time it will taken for the column surface temperature to rise to 27°C is  

17.1 hours

b)

The heat transfer to the column will stop when the center temperature of column reaches to the ambient temperature, which is 28°C.  

Maximum heat transfer between the ambient air and the column is

m = pV

= pπr₀²L

= (1600 kg/m³ × π × (0.15 m)² × (4 m)

= 452.389 kg

Qin = mCp [T∞ - Ti ]

= (452.389 kg) (0.84 kJ/kg.°C) (28 - 14)°C

= 5320 kJ  

Amount of heat transfer is 5320 kJ  

(c)

the amount of heat transfer until the surface temperature reaches to 27°C is

(T(0,t) - T∞) / Ti - T∞  = A₁e^(-λ₁²t')

= (1.3915)e^-(1.7240)² (0.6771)

= 0.1860

Once the constant J₁ = 0.5787 is determined from Table corresponding to the constant λ₁, the amount of heat transfer becomes  

(Q/Qmax)cyl = 1 - 2((T₀ - T∞) / ( Ti - T∞)) ((J₁(λ₁)) / λ₁)

= 1 - 2 × 0.1860 × (0.5787  / 1.7240)  

= 0.875

Q = 0.875Qmax

Q = 0.875(5320 kJ)  

Q = 4660 kJ

Amount of heat transfer until the surface temperature reaches 27°C is 4660 kJ

Answer:

a

Explanation:

Answer: 2.3 x 10^-7

Explanation:

When you move the decimal to the right, you decrease the exponent. So lets count how many spots you have to move the decimal spot to get an answer between 1 and 10. I counted seven spots.

So:

[tex]2.3 *10^-^7[/tex]

2.3 * 10 °−7

The degree indicates that the number is that small thing that floats above

Answer:

5m

Explanation:

Answer:

5

Explanation:

because that's the average of how far it when the most

Answer:

F = 1280 N

Explanation:

Given that,

Acceleration experienced by a space shuttle, a = 32 m/s²

Mass of the astronauts, m = 40 kg

We need to find the force experienced by the astronaut.

We know that the net force is equal to the product of acceleration and its mass. So,

F = ma

F = 40 kg × 32 m/s²

So,

F = 1280 N

So, 1280 N of force is experienced by the Astronaut.