Two kg of refrigerant 134a undergoes a polytropic process in a piston–cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80°c. Determine the work for the process, in kj.

Answers

Answer 1

The work done by polytropic process is -69.88 kJ.

The work for the polytropic process is determined using  

P . v^n = constant.

where P is pressure, V is specific volume

As we know that

W = m∫Pdv

W = m(P2v2 - P1v1) / (1 - n)

In order to evaluate this expression, we need to determine the specific volumes and the polytropic exponent, n.

State 1: v1 = vg1 = 0.0993 m3/kg

State 2: at 12 bar, 80oC; v2 = 0.02051 m3/kg

Hence by using polytropic exponent

P1 / P2 = (v2 / v1)^n

n = ln(2/12) / ln(0.02051/0.0993)

n = 1.136

Find the work done

W = m(P2v2 - P1v1) / (1 - n)

W = 2kg(12bar . 0.02051m³/kg - 2 . 0.0993) / (1 - 1.136) x (10⁵ N/m²/1 bar) x (1 kJ / 10³ Nm)

W = -69.88 kJ

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Related Questions

A weather balloon has a volume of 100L when it is released from above sea level, where the pressure is 101kPa. What will the balloon's volume when it reaches an altitude where the pressure is 43kPa?
Can someone please help me with this and quick??

Answers

The volume of the balloon is 234.88L.

What is volume?

Volume can be defined as the capacity of a solid shape.

To calculate the volume of the balloon, we use the formula below.

Formula:

PV = P'V'.......... Equation 1

Where:

P = Initial pressure of the balloonP' = Final pressure of the balloonV' = Initial volume of the balloonV = Final volume of the balloon

Make V' the subject of the equation

V' = PV/P'................. Equation 2

From the question,

Given:

P = 101 kPaV = 100 LP' = 43kPa

Substitute these values into equation 2

V' = 101×100/43V' = 234.88 L

Hence, The volume of the balloon is 234.88L.

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A man walks 20 km in 4 hours. Find his speed.
O 5 km/hr
O2 km/hr
O 10 km/hr
O1 km/hr

Answers

Answer: 5 km/hr

Explanation: 20Km / 4 hours is 5km a mile

His speed is 20/4 = 5 km/hr

meaning of quantity survey​

Answers

Explanation:

quantity surveying is the action or profession of a person who estimates the cost of the materials and labour necessary for a construction job.

A signal contains the following frequencies, 100 hz, 247 hz, and 750 hz. what is the nyquist frequency of the signal?

Answers

The nyquist frequency of the signal containing the following frequencies 100hz, 247hz and 750hz is taken to be calculated as 1500 hz.

Calculation

The provided frequencies are as follows:

100hz, 247hz, 750hz

Then the accurate Nyquist frequency can be taken out as

fs = 2 fmax

= 2 (750)

= 1500 Hz

Describe the Nyquist theorem in a few words.

The sampling theorem is another name for the Nyquist theorem. The rule is that a pure sine wave measurement, or sample rate, must be at least twice as frequent as the original to be accurately reproduced.

What is the formula for Nyquist’s theorem?

Nyquist explains that we can send data at a rate of up to C=2Blog2M bits per second in a channel with no noise. B is seen as the bandwidth (in Hz) and M is the number of signal levels.

The Nyquist frequency formula is what?

The Nyquist frequency can be defined as fn = 1/2t. When spectra for digital data are displayed, the highest frequency displayed is the Nyquist frequency.

For an IRIS type of broadband seismic stations, Δt = 0.05 s, so the Nyquist frequency is 10 Hz.

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An interior designer is choosing a paint color for a room and has two samples that are both blue, however one blue is described as brighter than the other. Both would have the same wavelength, but would differ based on what physical property of light?.

Answers

An interior designer is choosing a paint color for a room and has two samples that are both blue, however one blue is described as brighter than the other. Both would have the same wavelength but would differ due to the amplitude property of light.

The amplitude plays an important part in differentiating the same colors of the same wavelength. It tells us about the brightness or intensity of a certain light wave as compared to others of the same wavelength. So, whenever two same colors look different due to brightness, it is due to the amplitude property of the light.

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consider a long cylindrical charge distribution of radius r with a uniform charge density rho. find the electric field at distance r from the axis where r < r . assume the charge density is positive (rho > 0).

Answers

The electric field at distance r from the axis where r < r . assume the charge density is positive  E = p× r / 2 ×e₀

Given:

- Volume of cylinder V = pi×r² ×L

- area A = 2× pi ×r ×L

- permittivity of space : e₀

Finding :

Electric field E at distance r from the axis, where r < R.

Solution:

Step 1: Application of Gauss Law

Form a Gaussian surface within the cylinder with r < R. Th cylinder has two surfaces i.e curved surfaces and end caps. thanks to long charge distribution the flux through is zero, since the surface dA of end cap and E are at 90 degree angle to at least one another; hence, E . dA = E× dA ×cos(90) = 0.

For the curved surface we have:  

                 (surface integral) E.dA = Q_enclosed / e₀

Step 2: The charge enclosed (Q_enclosed) is function of r and proportional density:

                   Q_enclosed = p ×V

                                   Q_enclosed = p ×pi ×r² ×L

Step 3: the world of the curved surface:

                                  dA = 2× pi ×r ×L

Step 4: Computing E:

                         E×(2 ×pi ×r ×L) = p× pi ×r^2×  L / e₀

                                 E = p×r / 2×e₀

Charge density :

The charge density is that the measure of electric charge per unit area of a surface, or per unit volume of a body or field. The charge density tells us what proportion charge is stored in a particular field. Charge density are often determined in terms of volume, area, or length.

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A car travels 40 miles north in the first 40 minutes of a trip. The same car travels 30 miles west in the next 30 minutes of the trip. What can be said about the motion of the car?.

Answers

Answer: The car is travelling at a constant speed. Because it travells 30 miles in 30 minutes. While it travells 40 miles in 40 minutes.

Explanation:

Convert 500 cubic feet into gallons. Round your answer to the nearest whole number.

Answers

3740 US liquid gallons
The answer should be 3,740

a circular cylindrical post with a circumference of 4 feet has a string wrapped around it, spiraling from the bottom of the post to the top of the post. the string evenly loops around the post exactly four full times, starting at the bottom edge and finishing at the top edge. the height of the post is 12 feet. what is the length, in feet, of the string?

Answers

The length of the string wrapped around a circular cylindrical post is 20ft.

We have a circular cylinder and a string wrapped around it.

If we unwrap one complete revolution of string around the post. We have a rectangle. Having a width of 4ft (that is the circumference of the post.)

height of the post is 12 feet

Then height of the rectangle is. 12/4 = 3ft

The string evenly loops around the post exactly four full times, starting at the bottom edge and finishing at the top edge.

So the length of this is the hypotenuse of right triangle sides 3 and 4

then length determined using Pythagoras theorem

L² = 3²+4² = 25

L =√25 =5ft

Here we have three more similar triangles in  more 3 revolution.

1 revolution×5+ 3revolution×5

4×5 =20ft

The length of the string  wrapped around a circular cylindrical post is 20ft.

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A gust of wind blows an apple from a tree.
As the apple falls, the force of gravity on the apple is 9.16 N downward, and the force of the wind on the apple is 1.87 N to the right.
What is the direction of the net external force on the apple (measured from the downward vertical, so that the angle to the right of downward is positive)?
Answer in units of degrees

Answers

The direction of the apple is 78.5 degrees.

What is force?

We know that force is that which brings about motion. Force acts on an object when it is stationary and makes it to move or makes a moving object to change direction.

The magnitude and the direction of the vector is regarded as very important when we are trying to solve for a particular vector.

Now  we can see that the force of gravity acts vertically while the force that is exerted by the wind acts horizontally. This implies that we now have  right angled triangle and the direction of the force could be obtained geometrically as;

tan^-1(9.16 N/ 1.87 N)

= 78.5 degrees

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How do gender roles differ from gender stereotypes?:

Answers

The attitudes and expectations around gender roles are often founded on gender stereotypes, or oversimplified ideas about the attitudes, attributes, and behavior patterns of males and females, rather than on any inherent or natural gender distinctions.

Gender stereotypes are broadly accepted ideas about traits that are considered suitable for males and females. There really are gender stereotypes regarding character, profession, and skills. These prejudices are reflected in gender roles, which are commonplace actions.

Hence Understanding these beliefs and their origins is essential to conquering them even if they are typically damaging to society.

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before pushing down the piston, the pressure of the gas is 1.0 x 105 pa.pushinbg the piston reduces the volume of the gas from 500cm3 to 240cm3. calculate the final pressure of the gas

Answers

The final pressure of the gas is p2 = 2.085 * 10^5 pa.

Boyle's law is a gas law that states that the pressure exerted by a gas (of a given mass at a constant temperature) is inversely proportional to the volume it occupies. That is, if the temperature and quantity of gas are constant, the pressure and volume of the gas are inversely proportional.

Boyle's Law states that a change in the volume occupied by a gas (at a constant amount and temperature) leads to a change in the pressure exerted by the gas. The following mathematical formulation of this law is possible:

P1V1 = P2V2

Given,

Initial Volume, v1 = 500 cm3

Final Volume, v2 = 240 cm3

Initial Pressure, p1 = 1.0 * 10^5 pa

Final Pressure, p2

We know that,

p1 v1 = p2 v2

1.0 * 10^5 * 500 = p2 * 240

p2 = 2.085 * 10^5 pa

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problem 11.009 - slowing car - dependent multi-part problem - assign all parts skip to question note: this is a multi-part question. once an answer is submitted, you will be unable to return to this part. the brakes of a car are applied, causing it to slow down at a rate of 13 ft/s2. the car stops at 300 ft.

Answers

The velocity of the car before the brakes were applied is 88.32 ft / s

We know that,

a = ( v - u ) / t

s = ut + 1 / 2 a[tex]t^{2}[/tex]

where,

a = Acceleration

v = Final velocity

u = Initial velocity

t = Time taken

s = Displacement

Given that,

v = 0

s = 300 ft

a = - 13 ft / [tex]s^{2}[/tex]

a = ( v - u ) / t

- 13 = ( 0 - u ) / t

t = u / 13

s = ut + 1 / 2 a[tex]t^{2}[/tex]

300 = u ( u / 13 ) + 1 / 2 ( - 13 ) ( u / 13 [tex])^{2}[/tex]

300 = [tex]u^{2}[/tex] / 13 -  [tex]u^{2}[/tex] / 26

[tex]u^{2}[/tex] = 7800

u = 88.32 ft / s

Velocity is the rate of change of distance with respect to time. It is denoted by V. Its units are mostly m/s, ft/s etc.

Therefore, the velocity of the car before the brakes were applied is 88.32 ft / s

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When is the best time to stretch?
A.
After a workout session
B.
Before you exercise
C.
In the middle of a workout
D.
You don't need to stretch

Answers

Answer: B

Explanation:

B










Step by step Explanation:







An object is projected horizontally at 8.0m/s from he top of a 122.5m cliff. How far from the base of the cliff will the object strike the ground?

Answers

The object strikes 40.0 meters far from the base of the cliff on the ground.

Let us assume that the object strikes the ground after a time equal to 't' seconds. And horizontal distance covered by it in 't' seconds is x meters. The vertical distance traveled by it in 't' second would be equal to the height of the cliff.

Now for finding time 't' seconds

Vertical distance traveled = s = 122.5m

Initial vertical speed = u = 0 m/s

Acceleration due to gravity = g = 9.8 m/s²  

By using the second equation of motion:

s = ut + 1/2gt²

Put in the value

122.5 = (0)t + 1/2(9.8)t²

122.5 = 0 + 4.9t²

t² = 122.5/4.9

t² = 25

t =√25

t = 5 seconds

For finding the distance x meters

Horizontal speed = v = 8.0 m/s

Time taken = t = 5 s

Acceleration = 0 m/s

Using the formula, distance = speed ×  time

x = v × t

x = 8.0 × 5

x = 40.0 m

Therefore the object strikes 40.0 meters far from the base of the cliff on the ground.

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1) A man walks 10km north and then 10km west.

a) What distance has he covered?

b) How would you measure his
displacement?

c) What angle would his displacement be at compared to
north?

Answers

The distance covered by man was 20 km, his total displacement would be 14.14 km and the angle of his displacement would be 45° compared to the north.

What is displacement?

Displacement is defined as changes in an object's position referred to as displacement. It is a vector quantity that has both a direction and a magnitude.

As per the given condition,

Distance covered by man = 10 km + 10 km = 20 km

Total displacement will be the hypotenuse of two north and west sides.

⇒ Total displacement = √(10²+10²)

⇒ Total displacement = √(100+100)

⇒ Total displacement = √200

⇒ Total displacement = 10√2

⇒ Total displacement = 14.14 km

The angle of his displacement would be : tan⁻¹(10/10) = 45°

Hence, the distance covered by the man was 20 km, his total displacement would be 14.14 km and the angle of his displacement would be 45° compared to the north.

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problem 11.003 - mass on a spring - dependent multi-part problem - assign all parts skip to question note: this is a multi-part question. once an answer is submitted, you will be unable to return to this part. the vertical motion of mass a is defined by the relation x

Answers

The position, velocity, and acceleration of A

when t= 0.5 s are = 98.748 mm/s², respectively.

Steps of the equation:

This is a multi-part question: Once an answer is submitted, you will be unable to return to this part:

The vertical motion of mass A is defined by the relation x = cos (iot O.1sin (1Of, where x and tare expressed in mm and seconds, respectively:

Consider t = 0.5 s. Problem 11.003.

a Velocity and acceleration of a mass on a spring Determine the position, velocity; and acceleration of A (You must provide an answer before moving to the next part)

The position, velocity, and acceleration of A

when t= 0.5 s are

          = -0.379 mm,

          = -1.867| mm/s, and

          = 98.748 mm/s², respectively

What exactly is a dependency in Spring?

Dependency Injection is a key feature of the Spring framework that allows the Spring container to "inject" objects into other objects or "dependencies." Simply put, this allows for loose coupling of components and shifts responsibility for component management to the container.Spring IOC's primary functionality is dependency injection (Inversion of Control). The Spring-Core module is in charge of injecting dependencies via Constructor or Setter methods.

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Which measurement has three significant digits?
0.050 kg
0.205 s
500 m
1.030 g

Answers

0.205s considering 0.050 (2sf) , 500m (1sf), 1.030 (4sf)

An electron moving in a straight line has an initial speed of 2.320 x 10^7 m/s. It undergoes an acceleration of 2.20 x 10^10 m/s^2 [Bwd].
a. How long will it take to reach a speed of 3.42 x 10^5 m/s [Bwd]?
b. How far will it have travelled in this time?

Answers

KKdkekskAnswer:

Explanation:

help what does this mean

String instruments have different thicknesses of strings. This allows for the instrument to have different notes that give off different __________.


a. amplitude

b. pitch

c. wavelengths

d. rarefaction

Answers

the answer is amplitude

A car travels 40 miles north in the first 40 minutes of a trip. The same car travels 30 miles west in the next 30 minutes of the trip. What can be said about the motion of the car?.

Answers

It can be said that the car which travels first at 40 miles in 40 minutes and then 30 miles in 30 minutes is traveling at a constant speed.

The formula and procedure we will use to solve this exercise is:

v = x /t

Where:

x = distancet = timev = velocity

Information about the problem:

t₁ = 40 minx₁= 40 milest₂ = 30 minx₂= 30 milesv₁ = ?v₂ = ?

Applying the velocity formula for the first data information of the travel, we get:

v₁ = x₁ /t₁

v₁ = 40 miles /40 min

v₁ = 1 mile/min

Applying the velocity formula for the second data information of the travel, we get:

v₂ = x₂ /t₂

v₂ = 30 miles /30 min

v₂ = 1 mile/min

As we notice v₁ = v₂ that means that the car is traveling with a constant speed during the trip

What is velocity?

It is a physical quantity that indicates the displacement of a mobile per unit of time, it is expressed in units of distance per time, for example (miles/h, km/h).

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the escape speed from the earth is 1.12 ⇥104 m s 1, so that a gas molecule travelling away from the earth near the outer boundary of the earth’s atmosphere would, at this speed, be able to escape from the earth’s gravitational field and be lost to the atmosphere. at what temperature is the average speed of (a) oxygen molecules, and (b) helium atoms equal to 1.12 ⇥104 m s 1? (c) can you explain why our atmosphere contains oxygen but not helium?

Answers

Given Quantity

v esc =1.12×10 4  m/s: escape speed from the Earth =1.12×10  m/s: escape speed from the Earth

m = 2(1.66 \times 10^{-27}) = 3.32 \times 10^{-27}{kg}m=2(1.66×10 −27)=3.32×10 −27 kg: molecular mass of helium

We calculate the temperature at which helium atoms has an rms speed equal to the escape speed.

The rms speed is equal to the following

v rms​  = 3kT/m​ ​ (1)

where kk is the Boltzmann constant, TT is the temperature, and mm is the molecular mass.

Manipulating Equation (1)(1) to be equal to the escape speed, we can calculate the temperature to be

v esc= 3kT/m esc

​v esc= = 3kT/m esc

Tesc=mv2esc/3k

What is gravitational field?

A gravitational field is a framework used in physics to explain the effects that a large thing has on the area surrounding it, exerting a force on smaller, less massive bodies. As a result, a gravitational field, which is measured in n. per kilogram, is employed to describe gravitational phenomena.

Therefore,

the escape speed from the earth is 1.12 ⇥104 m s 1, so that a gas molecule travelling away from the earth near the outer boundary of the earth’s atmosphere would, at this speed, be able to escape from the earth’s gravitational field and be lost to the atmosphere. at what temperature is the average speed of (a) oxygen molecules, and (b) helium atoms equal to 1.12 ⇥104 m s 1? (c) can you explain why our atmosphere contains oxygen but not helium?

Given Quantity

v esc =1.12×10 4  m/s: escape speed from the Earth =1.12×10  m/s: escape speed from the Earth

$ k= 1.38 \times 10^{-3}$: Boltzmann constant

m = 2(1.66 \times 10^{-27}) = 3.32 \times 10^{-27}{kg}m=2(1.66×10 −27)=3.32×10 −27 kg: molecular mass of helium

We calculate the temperature at which helium atoms has an rms speed equal to the escape speed.

The rms speed is equal to the following

v rms​  = 3kT/m​ ​ (1)

where kk is the Boltzmann constant, TT is the temperature, and mm is the molecular mass.

Manipulating Equation (1)(1) to be equal to the escape speed, we can calculate the temperature to be

v esc= 3kT/m esc

​v esc= = 3kT/m esc

Tesc=mv2esc/3k

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If the green house effect did not exist at all,what would Erath would be like?

Answers

The heat generated by the Earth would keep passing radially outward from the Earth's surface into space if the natural greenhouse effect did not exist, and the Earth would have an average temperature of about -20°C.

What is greenhouse effect?

The greenhouse effect describes how "greenhouse gases" trap heat near the Earth's surface.

These heat-trapping gases act like a blanket wrapped around Earth, keeping it warmer than it would be without them.

Earth would turn into an icy wasteland if greenhouse gases were not present.

Greenhouse gases maintain our planet habitable by retaining some of the Earth's heat energy, preventing it from escaping into space. The greenhouse effect is the sequestration of heat.

Thus, the greenhouse effect can decrease the temperature of the Earth below average.

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When multiple radio telescopes are used for interferometry, resolving power is most improved by increasing.

Answers

Resolving power is most improved by increasing the distance between telescopes.

Relatively close objects, such binary stars or individual galaxies’ stars, occupy very small angles on telescopes. We require really huge apertures to resolve them. The resolving power of telescope is calculated by Rayleigh's formula,

∆ θ = 1.22λ/d

So, resolving power = 1/∆θ = d/1.22λ

The reciprocal of the smallest angle occupied at the telescope’s objective lens by two point objects that can just be recognised as distinct is the definition of a telescope’s resolving power.

A telescope Is an optical equipment that uses lenses, curved mirrors, or a combination of the two to view distant objects. Other tools can be used to view distant objects by their electromagnetic radiation emission, absorption, or reflection.

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calculate the deceleration of a bullet initially travelling at 360 m/s, if it is brought to rest after travelling 8.5 cm into a tree trunk which it has struck.

Answers

The de - acceleration of bullet from 360 m/s after it struck the tree trunk and was brought to rest is -152.54 x 10⁴ m/s².

What is Acceleration in Kinematics?

Acceleration is defined as the rate of change of velocity with respect to time. Mathematically -

a = Δv/Δt

Given is a bullet initially travelling at 360 m/s struck into a tree trunk 8.5 cm inside and comes to rest. From this, we can write

initial velocity [u] = 360 m/s

final velocity [v] = 0 m/s

distance travelled [d] = 8.5 cm = 0.085 m

The time span after which bullet comes to rest will be -

Δt = d/u

Δt = 0.085/360 = 2.36 x 10 ⁻⁴ seconds

a = Δv/Δt

Δv = 0 - 360 = - 360 m/s

a = (v - u)/Δt

a = - 360/(2.36 x 10 ⁻⁴)

a = - 152.54 x 10⁴ m/s²

Therefore, the de - acceleration of bullet from 360 m/s after it struck the tree trunk and was brought to rest is -152.54 x 10⁴ m/s².

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When performing a voltage drop test on a 12v blower motor circuit, the reading is 2.7 volts across the fan switch when closed. what is the maximum voltage available at the fan?

Answers

When performing a voltage drop test on a 12v blower motor circuit, the reading is 2.7 volts across the fan switch when closed. the maximum voltage available at the fan is

V=9.3 volts

This is further explained below.

What is voltage?

Generally, Electric potential difference, also known as voltage, electric pressure, or electric tension, is the amount of labor required per unit of charge to transfer an electrostatic test charge from one location to another.

In conclusion, When testing the voltage drop across the fan switch on a circuit with a 12v blower motor, the measurement is 2.7 volts. V=9.3 volts is the maximum power supply for the fan.

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As a freely falling object picks up downward speed, what happens to the power supplied by the gravitational force?.

Answers

As a freely falling object picks up downward speed, then the power supplied by gravitational force will increase.

We know that Power = work done /time

Power = W ×t and work = Force × displacement.

W= F(d) = F× speed/time (distance = speed /time)

So, if we increase the speed then work done will also increase, eventually it increases the power.

The longer an object is in free fall, the faster it falls toward the ground due to gravity. means it depend on the mass of object.

A falling object accelerates as it falls downward rapidly. The quantity of air resistance rises in proportion to the speed. The pull of gravity eventually is balanced by the force of air resistance as it grows. The item will cease accelerating since there is no net force at this point in time 0 newton.

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if the straight-line distance from her home to the university is 8.9 km in a direction 25° south of east, what was the magnitude of her average velocity in kilometers per hour?

Answers

The magnitude of her average velocity in kilometers is 29 km/h.

The average velocity of an object is defined as the average distance covered by an object in a given time interval. It can be presented in the unit as a meter per second or kilometer per second. It is represented by the symbol 'v'.

The straight line distance from her home is d.

d. = 8.9 km

The direction of her home = 50° south of east

The magnitude of her average velocity is,

[tex]Average \: velocity = \frac{ Distance \: trailed \: by \: the \: object}{ Time \: taken \: to{ cover \: the \: distance}}[/tex]

[tex] = \frac{8.9}{18} \times \frac{18}{1} [/tex]

= 29 km/h

Therefore, the magnitude of her average velocity in kilometers is 29 kilometers per hour.

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A body of mass 6kg falls under action of gravity at initial position a its pe is 480 j and ke is 0j during its downwards journey at point b its energies will be

Answers

During its downward journey at point b, its kinetic and potential energies will be mgh and 6gx respectively.  

Kinetic energy will be mg × ( total height = x ) and potential energy will be 6 g x. Let's assume that point B is located at  height x unit from the surface,

As we know , potential energy = m g h ( where m = mass of the body , g = gravitational acceleration and h = height from the surface )

so potential energy at point A = 480 j  or 6gh ( h = total height from surface )and for the point B it is , 6gx ( where g = 9.8 m/s²) .

At point A , total kinetic energy is 0 or, 1/2 mu² = 0

∵ u = 0,

So, initial velocity is zero ,

Now we will apply Newton's formula ,

and we will get , v² = u² + 2as

or, v² = 0 + 2 g h ( as acceleration = gravitational acceleration = g ; s = height h )

[ multiplying both side with 1/2 m ]

or , 1/2 m v² =  m g h

Kinetic energy = 1/2 m v² = m g h

[ h = ( total height - x )  at point B .  ]

Kinetic energy = m g ( total height - x ).

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the power rating of the resistors in our kits are 1/4 watt. that means the power dissipated by any resistor of resistance r should not exceed 250 mw. using the power formula p

Answers

Statement 1 and 3 are correct.

According to Ohm's law,

P = V I

V = I R

where,

P = Power

V = Voltage

I = Current

R =Resistance

Given that,

P = 250 * [tex]10^{-3}[/tex] W

If R = 10 Ω

P = [tex]I^{2}[/tex] R

[tex]I^{2}[/tex] = P / R

[tex]I^{2}[/tex] = 250 * [tex]10^{-3}[/tex] / 10

I = 15.81 * [tex]10^{-2}[/tex] A

V = 15.81 * [tex]10^{-2}[/tex] * 10

V = 1.581 V < 50 V

So statement 1 is correct

If the same method is applied for 100 Ω, the voltage would be 50 V which is greater than 5 V. So statement 2 is wrong

V = P / I

V = P R / V

V = [tex]\sqrt{0.25*R}[/tex]

According to this, statement 3 is correct and statement 4 is wrong.

Ohm's law states that, when two points have a potential difference, the current passing through the resistance is directly proportional to the voltage across the two points.

The given question is incomplete. The complete question is :

The power rating of the resistors in our kits are 1/4 watt. That means the power dissipated by any resistor of resistance R should not exceed 250 mW. Using the power formula P = Vxl and Ohm's law, which of the following is true? V is the voltage across the resistor and I is the current through it. (check all that apply)

The voltage V across a resistor of resistance 10 Ohms should be less than 50V The voltage V across a resistor of resistance 100 Ohms should be less than 5V The voltage V (in Volts) across a resistor of resistance R (in Ohms) should be less than √250 x R The voltage V (in Volts) across a resistor of resistance R (in Ohms) should be less than √0.25 XR

Therefore, the statements 1 and 3 are true.

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