One mol of a perfect, monatomic gas expands reversibly and isothermally at 300 K from a pressure of 10 atm to a pressure of 2 atm. Determine the value of q, w.

(b) Now assume the gas expands by the same amount again isothermally but now irre-

versibly against 1 atm pressure (instead of reversible expansion) and calculate again q, w, delta U and delta H.

Answers

Answer 1

Answer:

Explanation:

Given

1 mole of perfect, monoatomic gas

initial Temperature[tex](T_i)=300 K[/tex]

[tex]P_i=10 atm[/tex]

[tex]P_f=2 atm[/tex]

Work done in iso-thermal process[tex]=P_iV_iln\frac{P_i}{P_f}[/tex]

[tex]P_i[/tex]=initial pressure

[tex]P_f[/tex]=Final Pressure

[tex]W=10\times 2.463\times ln\frac{10}{2}=39.64 J [/tex]

Since it is a iso-thermal process therefore q=w

Therefore q=39.64 J

(b)if the gas expands by the same amount again isotherm-ally and irreversibly

work done is[tex]=P\Delta V[/tex]

[tex]V_1=\frac{RT_1}{P_1}=\frac{1\times 0.0821\times 300}{10}=2.463 L[/tex]

[tex]V_2=\frac{RT_2}{P_2}=\frac{1\times 0.0821\times 300}{2}=12.315 L[/tex]

[tex]\Delta W=1\times (12.315-2.463)=9.852 J[/tex]

[tex]\Delta q=\Delta W=9.852 J[/tex]

[tex]\Delta U=0[/tex]


Related Questions

Three resistors are connected in series across a battery. The value of each resistance and its maximum power rating are as follows: 6.7Ω and 15.9 W, 30.4Ω and 9.12 W, and 16.3Ω and 12.3 W. (a) What is the greatest voltage that the battery can have without one of the resistors burning up? (b) How much power does the battery deliver to the circuit in (a)?

Answers

Answer:

a) greatest voltage = 29.25 V

b) power = 16 W

Explanation:

The total resistance R of the three resistors in series is:

[tex]R = (6.7 + 30.4 + 16.3) \Omega = 53.4 \Omega[/tex]  

a) The greatest current I is the one that will burn the resistor with lower power rating, which is 9.12 W:

[tex]P_{max} = I_{max}^2 R = I_{max}^2 30.4\Omega = 9.12W\\I_{max} = 0.54 A[/tex]

The voltage is:

[tex]V_{max}=IR = 0.54*53.4V= 29.25 V[/tex]

b) When the current is 0.54 A, the power is:

[tex]P = RI^2=53.4*0.3 W = 16W[/tex]

A force of magnitude 33.73 lb directed toward the right is exerted on an object. What other force must be applied to the object so that the resultant force is zero?

Answers

Final answer:

An additional force of 33.73 lb must be applied to the left to cancel out the initial force and create a resultant force of zero, according to Newton's first law of motion.

Explanation:

To ensure that the resultant force on the object is zero, another force of equal magnitude but in the opposite direction must be applied. In this case, since a force of 33.73 lb is directed toward the right, an additional force must be applied to the left with the same magnitude, i.e., 33.73 lb to the left. This balances out the forces acting upon the object, creating a state of equilibrium where the sum of the forces equals zero, thus satisfying Newton's first law of motion.

Now, considering the provided example where a man applies a force of +50 N, it's clear that the force of friction opposing the motion must also be 50 N but in the negative direction (-50 N) for the forces to cancel each other and fulfill the condition of Newton’s first law where Fnet = 0.

In the context of three forces acting on an object, discussing the necessary condition for an object to move straight down, the forces in the horizontal plane (to the right and left) must be balanced. This means that force A and force B, which act in opposite directions, must be equal in magnitude.

A ball is thrown vertically upwards with an initial velocity of 20.00 m/s. Neglecting air resistance, how long is the ball in the air? What is the greatest height reached by the ball? Also calculate the time at which the ascending ball reaches a height of 15 m above the ground.

Answers

Final answer:

The time for projectile motion is determined completely by the vertical motion. A ball thrown vertically upwards with an initial velocity of 20.00 m/s spends approximately 4 seconds in the air and reaches its greatest height after approximately 2 seconds. The time at which the ascending ball reaches a height of 15 m above the ground can be found by setting y = 15 m and solving for t.

Explanation:

The time for projectile motion is determined completely by the vertical motion. Thus, any projectile that has an initial vertical velocity of 20.00 m/s and lands 10.0 m above its starting altitude spends approximately 4 seconds in the air. The greatest height reached by the ball can be determined by using the equation for vertical motion: y = yo + voyt - 1/2gt^2. Plugging in the given values and solving for t, we find that the ball reaches its greatest height after approximately 2 seconds, and the time at which the ascending ball reaches a height of 15 m above the ground can be found by setting y = 15 m and solving for t.

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A 133.7 ft3 volume of liquid hydrogen rocket fuel has a mass of 268 kg. Calculate: the weight of the fuel at standard (Earth) sea level conditions in N and Ibr, the density of the fuel in kg/m3, and the specific volume in ft3/lbm (Ibm=pound-mass, which is not the same as a a lbf or a slug)

Answers

First, let's make some convertions:

[tex]268kg*\frac{1 lbm}{0.454kg}= 590.84 lbm[/tex]

[tex]133.7 ft^3*\frac{1m^3}{35.3147ft^3} = 3.78m^3[/tex]

a) weight of the fuel:

Newtons: The weight in newtons is equal to the mass in kilograms times the gravity in m/s^2.

[tex]W = m*g = 268kg*9.81m/s^2=2629.08 N[/tex]

lbf: The weight inlbf is equal to the mass in slugs times the gravity in ft/s^2.

[tex]W= m*g = 590.84 lbm *\frac{1 slug}{32.174lbm} *32.174ft/s^2 = 590.84 lbf[/tex]

b) density:

The density is the mass in kg of the fuel divided by its volume in m^3:

[tex]d = \frac{m}{v} =\frac{268kg}{3.78m^3} =70.9 kg/m^3[/tex]

c) specific volume:

The specific volume is the volume in ft^3 of the fuel divided by its mass in lbm:

[tex]v_{sp} = \frac{v}{m} =\frac{133.7 ft^3}{590.84 lbm} = 0.226 ft^3/lbm[/tex]

The population mean on a statistics exam is 72, with a standard deviation of 12. The population average on the class project is 95, with a standard deviation of 4. If the exam is 70% of the final grade and the project 30%, what are the mean and standard deviation of final grades?

Answers

Answer:

mean = 54

standard deviation = 6.24

Explanation:

given data

mean a = 72

standard deviation σx = 12

average b = 95

standard deviation σy = 4

final grade Z = 70%  = 0.70

project y = 30%  = 0.30

to find out

mean and standard deviation

solution

final grade equation will be here

final grade = 0.70x + 0.30 y   .....a

here x is statics grade and y is class project

so

mean will be 0.70x + 0.30 y

mean = 0.70 (a) + 0.30 (b)

mean = 0.70 (12) + 0.30 (95)

mean = 54

and

standard deviation = 0.70x + 0.30 y

standard deviation = 0.70(σx) + 0.30 (σy)

standard deviation = 0.70(12) + 0.30 (4)

standard deviation = 6.24

Describe how the motion of a planet (like Mars) among the stars of the zodiac on the sky is qualitatively different from the motion of an object like our Sun among the stars of the zodiac.

Answers

Final answer:

Planets like Mars exhibit direct and retrograde motion, resulting in complex paths across the night sky, which differ from the Sun's steady eastward movement along the ecliptic through the zodiac signs. Earth's faster orbit leads to the phenomenon of retrograde motion when observing other planets.

Explanation:

The motion of planets like Mars among the stars of the zodiac is different from the motion of the Sun because planets exhibit both direct motion and retrograde motion in their paths across the sky, as observed from Earth. Planets periodically appear to move in the opposite direction in the sky, known as retrograde motion, while the Sun moves steadily along the ecliptic through the zodiac signs. This distinct planetary motion is due to the orbital speed and path of Earth relative to other planets, leading to the phenomenon where Earth, moving faster along its orbit, occasionally overtakes other planets like Mars, changing how these planets appear to move against the backdrop of stars.

Additionally, planets can have stationary points where they appear to pause before they switch from direct to retrograde motion or vice versa. These motions are perceived from Earth because of the combination of the planets' own orbital movement around the Sun and Earth's simultaneous revolution. By contrast, the Sun follows a consistent eastward path among the fixed stars, circling the zodiac once per year, spending about a month in each zodiac sign.

For every action force, there is: A. a net force. B. an unbalanced force. C. a friction force. D. an equal and opposite force. E. all of these

Answers

Answer:

The correct option is 'D': Equal and opposite force.

Explanation:

We know from Newton's third law of motion

"For every action there exists an equal and opposite reaction".

The statement is further explained as

If there exists a force from Body 1 to Body 2 then Body 2 must also exert an equal and opposite force on the Body 1.

In simple terms we can say that the action and the reaction forces exist in pairs and are always present if any one among them is present.

A person walks 27.0° north of east for 4.00 km. How far due north and how far due east would she have to walk to arrive at the same location?

Answers

Answer:

Along North,  1.816 km

Along east , 3.564 km

Explanation:

d = 4 km 27° North of east

As we need to find the distance traveled due north and the distance traveled due east, they are the components along north and along east. The component along north is the vertical component and the distance traveled along east is the horizontal component.

Distance traveled due North

y = d Sin 27 = 4 Sin 27 = 1.816 km

Distance traveled due east

x = d cos 27 = 4 cos 27 = 3.564 km

A crane carries a 1600 kg car at 1.5 m/s^2 with a chain that has a negligible mass. If the coefficient of kinetic friction between the wheels of the car and the road is 0.3, what is the tension in the chain? a. 3.8 kN
b. 5.9 kN
c. 6.7 kN
d. 7.1 kN

Answers

Answer:

option (d) 7.1 kN

Explanation:

Given:

Mass of the car, m = 1600 kg

Acceleration of the car, a = 1.5 m/s²

Coefficient of kinetic friction = 0.3

let the tension be 'T'

Now,

ma = T - f .................(1)

where f is the frictional force

also,

f = 0.3 × mg

where g is the acceleration due to the gravity

thus,

f = 0.3 × 1600 × 9.81 =

therefore,

equation 1 becomes

1600 × 1.5 = T - 4708.8

or

T = 2400 + 4708.8

or

T = 7108.8 N

or

T = 7.108 kN

Hence,

The correct answer is option (d) 7.1 kN

A pinhole camera is just a rectangular box with a tiny hole in one face. The film is on the face opposite this hole, and that is where the image is formed. The camera forms an image without a lens. A certain pinhole camera is a box that is 20.0 cmsquare and 22.0 cm deep, with the hole in the middle of one of the 20.0 cm × 20.0 cm faces. If this camera is used to photograph a fierce chicken that is 18.0 cm high and 2.00 m in front of the camera, how large is the image of this bird on the film?What is the magnification of this camera?

Answers

Answer:

Size of image: 1.8 cm inverted

Magnification of camera: -0.1

Explanation:

Given:

[tex]h_o[/tex] = size of bird = 18 cm[tex]u[/tex] = distance of the bird from the camera = 2 m = 200 cm [tex]v[/tex] = distance of the film from the camera = 20 cm

Assume:

[tex]m[/tex] = magnification of the camera[tex]h_i[/tex] = size of image of the bird

Using sign convention, we have

[tex]u = -200\ cm\\v = 20\ cm\\h_o = 18\ cm[/tex]

The hole in the pinhole camera behaves as a convex lens. The other face opposite to the hole face behaves like a film where the image is formed to be seen. So, using the formula of magnification, we have

[tex]m = \dfrac{h_i}{h_o}=\dfrac{v}{u}\\\Rightarrow  \dfrac{h_i}{h_o}=\dfrac{v}{u}\\\Rightarrow  h_i=\dfrac{v}{u}h_o\\\Rightarrow  h_i=\dfrac{20}{-200}\times 18\\\Rightarrow  h_i=-1.8 cm[/tex]

This means the image of the bird measures 1.8 cm in length where negative sign in the calculation represents that the image formed is inverted.

Hence, the image of the bird on the film is 1.8 cm large.

Now, again using the formula of magnification, we have

[tex]m = \dfrac{h_i}{h_o}\\\Rightarrow m = \dfrac{-1.8}{18}\\\Rightarrow m =-0.1[/tex]

Hence, the magnification of the camera is -0.1.

Final answer:

In a pinhole camera, image size = object size * (camera depth / object distance). For a chicken 18 cm tall standing 2 meters away, the image size will be 0.198 cm. The magnification, or size of the image compared to the object, will be 0.011 or 1.1%

Explanation:

The size of the image formed by a pinhole camera is given by the formula: image size = object size * (camera depth / object distance). Substituting the values in this formula, image size = 18 cm * (22 cm / 2 m) = 0.198 cm. This tells us that the fierce chicken's image will be about 0.198 cm high on the film.

Next, the magnification of the camera is the ratio of the image size to the object size. So the magnification is 0.198 cm / 18 cm = 0.011. In other words, the image on the film is about 1.1% the size of the actual object.

Note:

These calculations are based on the simple model of a pinhole camera where only rays of light traveling in straight lines are considered. The actual picture may differ due to factors like the scattering of light.

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A player kicks a football (from the ground) at an initial angle of 30°. The football is in the air for 2.4 s before it hits an opposing player. The opposing player was a horizontal distance x = 50 m away from where the football was kicked. What was the initial horizontal velocity component of the football?

Answers

Answer:

The initial horizontal velocity was 21 m/s

Explanation:

Please, see the figure for a better understanding of the problem.

The equation for the position of an object moving in a parabolic trajectory is as follows:

r = (x0 + v0 · t · cos α, y0 + v0 · t · sin α + 1/2 · g ·t²)

Where:

r = vector position at time t

x0 = initial horizontal position

v0 = initial velocity

t = time

α = launching angle

y0 = initial vertical position

g = acceleration due to gravity

Notice that at time t = 2.4 s the vector "r" is the one in the figure. We know that the x-component of that vector is 50 m. Then using the equation for the x-component of the vector "r", we can calculate the initial velocity:

x = x0 + v0 · t · cos α

Let´s place the center of the frame of reference at the point of the kick so that x0 = 0.

x =  v0 · t · cos α

x/t = v0 · cos α

Notice in the figure that v0 · cos 30° = v0x which is the initial horizontal velocity. Remember trigonometry of right triangles:

cos α = adjacent / hypotenuse = v0x / v0

Then:

50 m/ 2.4 s = v0 · cos 30° = v0x

v0x = 21 m/s

A race car starts at rest and speeds up to 40 m/s in a distance of 100 m. Determine the acceleration of the car.

Answers

Answer:

Acceleration of the car, [tex]a=8\ m/s^2[/tex]

Explanation:

Given that,

Initial speed of the car, u = 0 (at rest)

Final speed of the car, v = 40 m/s

Distance covered, s = 100 m

We need to find the acceleration of the car. It can be calculated using third equation of motion as :

[tex]v^2-u^2=2as[/tex]

a is the acceleration of the car

[tex]a=\dfrac{v^2}{2s}[/tex]

[tex]a=\dfrac{(40)^2}{2\times 100}[/tex]

[tex]a=8\ m/s^2[/tex]

So, the acceleration of the car is [tex]8\ m/s^2[/tex]. Hence, this is the required solution

According to a rule-of-thumb, every five seconds between a lightning flash and the following thunder gives the distance to the flash in miles. Assuming that the flash of light arrives in essentially no time at all, estimate the speed of sound in m/s from this rule. What would be the rule for kilometers?

Answers

Answer:

speed of sound = 321 m/s

Rule of thumb for kilometers: 1 km every 3 seconds

Explanation:

Hi!

If a thunder originates at a place a distance D from you, and it takes time T for its sound to reach you, then:

[tex]V = \frac{D}{T}[/tex]

Whre V is the speed of sound. Time T is the time elapsed between the moment you see the flash (becuase of the assumption of tha it takes no time for the light to reach you) and the moment you hear the thunder. Then

[tex]V = \frac{1mile}{5\;s} =\frac{1609.34 \;m}{5\;s} = 321\frac{m}{s}[/tex]

To calculate the rule in kilometers:

[tex]T = \frac{1\;km}{321*10^{-3} \frac{km}{s}} \approx 3\; s[/tex]

Final answer:

The estimated speed of sound derived from the rule of thumb is approximately 322 m/s. For the rule in kilometers, each five seconds would represent about 1.609 kilometers.

Explanation:

The rule-of-thumb that every five seconds between a lightning flash and the accompanying thunder equates to one mile of distance is based on the speed of sound. To convert this to meters per second we must know that 1 mile approximately equals 1609.34 meters. Therefore, if light travels nearly instantaneously, and one mile is covered in five seconds, the speed of sound can be estimated as about 1609.34 m/5 s or approximately 322 m/s.

For the rule in kilometers, we need to convert miles into kilometers. As 1 mile is approximately 1.609 kilometers, the rule of thumb in kilometers would be that each five seconds would represent 1.609 kilometers.

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The route followed by a hiker consists of three displacement vectors, X, Y and Z. Vector X is along a measured trail and is 1430m in a direction 42 degrees north of east. Vector Y is along a measured trail that goes 2200m due south. The hiker then follows vector Z and ends up back where they started, so that X + Y + Z = 0. Find the magnitude of Z and an angle that specifies its direction.

Answers

Answer:

magnitude : 1635.43 mAngle: 130°28'20'' north of east

Explanation:

First, we will find the Cartesian Representation of the [tex]\vec{X}[/tex] and [tex]\vec{Y}[/tex] vectors. We can do this, using the formula

[tex]\vec{A}= | \vec{A} | \ ( \ cos(\theta) \ , \ sin (\theta) \ )[/tex]

where [tex]| \vec{A} |[/tex] its the magnitude of the vector and θ the angle. For  [tex]\vec{X}[/tex] we have:

[tex]\vec{X}= 1430 m \ ( \ cos( 42 \°) \ , \ sin (42 \°) \ )[/tex]

[tex]\vec{X}= ( \ 1062.70 m \ , \ 956.86 m \ )[/tex]

where the unit vector [tex]\hat{i}[/tex] points east, and [tex]\hat{j}[/tex] points north. Now, the [tex]\vec{Y}[/tex] will be:

[tex]\vec{Y}= - 2200 m \hat{j} = ( \ 0 \ , \ - 2200 m \ )[/tex]

Now, taking the sum:

[tex]\vec{X} + \vec{Y} + \vec{Z} = 0[/tex]

This is

[tex]\vec{Z} = - \vec{X} - \vec{Y}[/tex]

[tex](Z_x , Z_y) = - ( \ 1062.70 m \ , \ 956.86 m \ ) - ( \ 0 \ , \ - 2200 m \ )[/tex]

[tex](Z_x , Z_y) = ( \ - 1062.70 m \ ,  \ 2200 m \ - \ 956.86 m \ )[/tex]

[tex](Z_x , Z_y) = ( \ - 1062.70 m \ ,  \ 1243.14 m\ )[/tex]

Now, for the magnitude, we just have to take its length:

[tex]|\vec{Z}| = \sqrt{Z_x^2 + Z_y^2}[/tex]

[tex]|\vec{Z}| = \sqrt{(- 1062.70 m)^2 + (1243.14 m)^2}[/tex]

[tex]|\vec{Z}| = 1635.43 m[/tex]

For its angle, as the vector lays in the second quadrant, we can use:

[tex]\theta = 180\° - arctan(\frac{1243.14 m}{ - 1062.70 m})  [/tex]

[tex]\theta = 180\° - arctan( -1.1720)  [/tex]

[tex]\theta = 180\° - 45\°31'40'' [/tex]

[tex]\theta = 130\°28'20''  [/tex]

You drop two rocks. one rock has a mass of 8kg and the other a mass of 7kg. The 8kg rock falls no faster than the 7kg rock for what reason. is it due to force of gravity for both being the same?

Answers

Answer:

The gravitational force is significantly constant.

Explanation:

The gravitational force is expressed as:

F= G*M*m/d^2

G= Gravitational constant

M= in this case it is the mass of the planet

m= mass of the rock

d= distance of the rocks from the ground (suppose both at the same height for better comparison)

At the same time, we know that the force that each rock experiences is equal to the product of the mass due to acceleration:

F=m*a

We can match both expressions for F:

G*M*m/d^2 = m*a

we simplify m, and we obtain that the acceleration is independent of the mass of the attracted bodies:

a= G*M/d^2

If a car stops suddenly, you feel "thrown forward." We’d like to understand what happens to the passengers as a car stops. Imagine yourself sitting on a very slippery bench inside a car. This bench has no friction, no seat back, and there’s nothing for you to hold onto.(a) identify all of the forces action on you as thecar travels at a perfectly steady speed on level ground.(b) repeat part A with the car slowing down(c) describe what happens to you as the car slowsdown(d) suppose now that the bench is not slippery. as the carslows down, you stay on the bench and dont slide off. what force isresponsible for you deceleration?

Answers

A)

The forces acting on you are:

The gravitational pull of the Earth (an others Celestial objects)The Normal Force that balance the gravitational pull and points upward.

That is. There is not need for any other force, cause the car its going at constant speed, so the acceleration its zero, as the net force its mass multiplied by acceleration, the net force is zero.

B)

The forces acting on you are:

The gravitational pull of the Earth (an others Celestial objects)The Normal Force that balance the gravitational pull and points upward.

That is. Again. The car its slowing down. But, it cant apply a force in you against the direction of movement to slow you down.

C)

As you can't be slowed down, you will go forward at the same speed you had when the car went steady, and will crash against whatever its in front of you.

D)

The friction force, will pull you against the direction of movement, and slow you down will the car slows down.

Final answer:

When a car moves at a steady pace, the forces acting on a passenger include gravity and the normal force from the bench. When the car begins to slow down, the passenger experiences inertia, which might give the effect of being 'pushed' forward. If the bench is not slippery, friction will be the force that aids in decelerating the passenger along with the car.

Explanation:

(a) If you are sitting on a frictionless bench in a car that is moving at a perfectly steady speed, the forces acting on you are: the gravitational force directed down and the normal force from the bench acting upward. Since the car moves at a constant speed, there is no horizontal force.

(b) If the car starts slowing down, then in addition to the forces mentioned before, there is one more force in play, which is inertia. It's not a force like gravity or the normal force, but it is a consequence of Newton's first law of motion. You experience this as a force pushing you forward, even though the car is slowing down or stopping.

(c) Because of inertia, as the car slows down, you tend to keep moving. Without friction or anything to hold onto, you would slide off the bench and continue moving forward at the original speed of the car.

(d) If the bench is not slippery and you don't slide off as the car slows down, the force responsible for your deceleration is friction. Even though you can't feel it, friction between you and the bench affects you when the car decelerates.

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What voltage must be applied to an 6 nF capacitor to store 0.14 mC of charge? Give answer in terms of kV.

Answers

Answer:

[tex]V=23.3kV[/tex]

Explanation:

Definition of the capacitance C, where a voltage V is applied and a charge Q is stored:

[tex]Q=C*V[/tex]

We solve to find V:

[tex]V=Q/C=0.14*10^{-3}C/6*10^{-9}F)=2.33*10^{4}V=23.3kV[/tex]

A 39-foot ladder is leaning against a vertical wall. If the bottom of the ladder is being pulled away from the wall at the rate of 8 feet per second, at what rate is the area of the triangle formed by the wall, the ground, and the ladder changing, in square feet per second, at the instant the bottom of the ladder is 36 feet from the wall?

Answers

Final answer:

The rate at which the area of the triangle formed by the wall, the ground, and the ladder is changing, at the instant the bottom of the ladder is 36 feet from the wall, is -216 square feet per second.

Explanation:

This question revolves around the concept of related rates in calculus. The area of the triangle formed by the ground, the wall, and the ladder is given by the formula ½ * base * height. In this situation, the base is x, which represents the distance from the wall to the base of the ladder, and the height is the vertical reach of the ladder onto the wall, represented by y (which can be found using the Pythagorean theorem). Differentiating this equation with respect to time gives us dA/dt = ½ (x dy/dt + y dx/dt).

Given that dx/dt is 8 feet per second, and x=36 feet, to find dy/dt, we use the Pythagorean relationship (39² = 36² + y²), and solve for y to get y = 15 feet. Therefore, substituting all these values into the equation we find:** dA/dt = -216 sq.ft/sec**.

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The area of the triangle is changing at a rate of ( -285.6 ) square feet per second at the instant the bottom of the ladder is 36 feet from the wall. The negative sign indicates that the area is decreasing.

Let ( x ) be the distance of the bottom of the ladder from the wall, and ( y) be the height of the ladder on the wall. We are given that [tex]\( \frac{dx}{dt} = 8 \)[/tex] feet per second, and we want to find [tex]\( \frac{dA}{dt} \) when \( x = 36 \) feet.[/tex]

Using the Pythagorean theorem, we have [tex]\( x^2 + y^2 = 39^2 \).[/tex]Differentiating both sides with respect to time ( t ), we get:

[tex]\[ 2x\frac{dx}{dt} + 2y\frac{dy}{dt} = 0 \][/tex]

We can solve for [tex]\( \frac{dy}{dt} \):[/tex]

[tex]\[ 2y\frac{dy}{dt} = -2x\frac{dx}{dt} \][/tex]

[tex]\[ \frac{dy}{dt} = -\frac{x}{y}\frac{dx}{dt} \][/tex]

Now, we can express the area ( A ) in terms of ( x ) and ( y ):

[tex]\[ A = \frac{1}{2}xy \][/tex]

Differentiating ( A ) with respect to time ( t ), we get:

[tex]\[ \frac{dA}{dt} = \frac{1}{2}\left(x\frac{dy}{dt} + y\frac{dx}{dt}\right) \][/tex]

Substituting [tex]\( \frac{dy}{dt} \)[/tex] from above, we have:

[tex]\[ \frac{dA}{dt} = \frac{1}{2}\left(x\left(-\frac{x}{y}\frac{dx}{dt}\right) + y\frac{dx}{dt}\right) \][/tex]

[tex]\[ \frac{dA}{dt} = \frac{1}{2}\left(-\frac{x^2}{y}\frac{dx}{dt} + y\frac{dx}{dt}\right) \][/tex]

[tex]\[ \frac{dA}{dt} = \frac{1}{2}\left(y - \frac{x^2}{y}\right)\frac{dx}{dt} \][/tex]

We know [tex]\( \frac{dx}{dt} = 8 \)[/tex] feet per second, and we need to find [tex]\( \frac{dA}{dt} \)[/tex]when ( x = 36 ) feet. To find ( y ) at this instant, we use the Pythagorean theorem:

[tex]\[ 36^2 + y^2 = 39^2 \][/tex]

[tex]\[ y^2 = 39^2 - 36^2 \][/tex]

[tex]\[ y^2 = 1521 - 1296 \][/tex]

[tex]\[ y^2 = 225 \][/tex]

[tex]\[ y = 15 \][/tex]

Now we can find [tex]\( \frac{dA}{dt} \):[/tex]

[tex]\[ \frac{dA}{dt} = \frac{1}{2}\left(15 - \frac{36^2}{15}\right) \times 8 \][/tex]

[tex]\[ \frac{dA}{dt} = 4\left(15 - \frac{1296}{15}\right) \][/tex]

[tex]\[ \frac{dA}{dt} = 4\left(15 - 86.4\right) \][/tex]

[tex]\[ \frac{dA}{dt} = 4\left(-71.4\right) \][/tex]

[tex]\[ \frac{dA}{dt} = -285.6 \][/tex]

So, the area of the triangle is changing at a rate of ( -285.6 ) square feet per second at the instant the bottom of the ladder is 36 feet from the wall. The negative sign indicates that the area is decreasing.

If a marathon runner averages 9.51 mi/hr, how long does it take him to run a 26.220-mile marathon. Express your answers in hours, minutes, and seconds.

Answers

Explanation:

Speed of the marathon runner, v = 9.51 mi/hr

Distance covered by the runner, d = 26.220 mile

Let t is the time taken by the marathon runner. We know that the speed of the runner is given by total distance divided by total time taken. Mathematically, it is given by :

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

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

[tex]t=\dfrac{26.220\ mi}{9.51\ mi/hr}[/tex]

t = 2.75 hours

Since, 1 hour = 60 minutes

t = 165 minutes

Since, 1 minute = 60 seconds

t = 9900 seconds

Hence, this is the required solution.

An amplitude modulation transmitter radiates 20 KW. If the modulation index is 0.7, find the magnitude of the carrier power?

Answers

Answer:

carrier power is 16.1 kW

Explanation:

given data

power transmit P = 20 kW

modulation index m = 0.7

to find out

carrier power

solution

we will apply here power transmit equation that is express as

[tex]P = 1 + \frac{m^2}{2} * carrier power[/tex]   ...............1

put here all value in equation 1  we get carrier power

[tex]P = 1 + \frac{m^2}{2} * carrier power[/tex]

[tex]20 = 1 + \frac{0.7^2}{2} * carrier power[/tex]

solve it we get

carrier power = 16.1

so carrier power is 16.1 kW

A car traveling 77 km/h slows down at a constant 0.45 m/s^2 just by "letting up on the gas." --Part a : Calculate the distance the car coasts before it stops.
--Part b: Calculate the time it takes to stop.
--Part c: Calculate the distance it travels during the first second.
--Part d: Calculate the distance it travels during the fifth second. Need help with all parts A-D, please show all work and formulas used.

Answers

Answer:

(a) 508.37 m

(b) 47.53 s

(c) 21.165 m

(d) 19.365 m

Explanation:

initial velocity, u = 77 km/h = 21.39 m/s

acceleration, a = - 0.45 m/s^2

(a) final velocity, v = 0

Let the distance traveled is s.

Use third equation of motion

[tex]v^{2}=u^{2}+2as[/tex]

[tex]0^{2}=21.39^{2}-2 \times 0.45 \times s[/tex]

s = 508.37 m

(b) Let t be the time taken to stop.

Use first equation of motion

v = u + at

0 = 21.39 - 0.45 t

t = 47.53 s

(c) Use the formula for the distance traveled in nth second

[tex]s_{n^{th}=u+\frac{1}{2}a\left ( 2n-1 \right )}[/tex]

where n be the number of second, a be the acceleration, u be the initial velocity.

put n = 1, u = 21.39 m/s , a = - 0.45m/s^2

[tex]s_{n^{th}=21.39-\frac{1}{2}\times 0.45\left ( 2\times 1-1 \right )}[/tex]

[tex]s_{n^{th}=21.165m[/tex]

(d)  Use the formula for the distance traveled in nth second

[tex]s_{n^{th}=u+\frac{1}{2}a\left ( 2n-1 \right )}[/tex]

where n be the number of second, a be the acceleration, u be the initial velocity.

put n = 5, u = 21.39 m/s , a = - 0.45m/s^2

[tex]s_{n^{th}=21.39-\frac{1}{2}\times 0.45\left ( 2\times 5-1 \right )}[/tex]

[tex]s_{n^{th}=19.365m[/tex]

A basketball player wishes to make a stunning last-second basket. With .8 seconds on the clock, she wants the ball to enter the hoop (height 3.05m) as time expires in the game. She shoots the ball with an initial speed of 7 m/s, from 2.1 meters above the ground.

1. At what angle (from the HORIZONTAL) does she shoot the ball?

2. Draw qualitatively accurate position, velocity, and acceleration graphs for both dimensions of the ball's motion while it is in flight.

Answers

Answer:

(1) [tex]46.86^\circ[/tex]

(2) Diagram has been attached in the solution.

Explanation:

This question is from projectile motion.

From the given question, we will discuss the motion of the basket ball only in the vertical direction from which we will be able to find out the angle of the initial velocity with the horizontal with which it should be shoot to enter the hoop.

Part (1):

Let us assume:

[tex]y_i[/tex] = initial position of the basket ball = 2.1 m[tex]y_f[/tex] = final position of the basket ball = 3.05 m[tex]a_y[/tex] = acceleration of the ball along the vertical = [tex]-9.8\ m/s^2[/tex][tex]t[/tex] = time taken to reach the goal = 0.8 s[tex]\theta[/tex] = angle of the initial velocity with the horizontal[tex]u[/tex] = initial speed of the ball = 7 m/s[tex]u_y[/tex] = initial vertical velocity of the ball = u\sin \theta

Using the equation of motion for constant acceleration, we have

[tex]y_f-y_i=u_yt+\dfrac{1}{2}a_yt^2\\\Rightarrow 3.05-2.1=u\sin \theta (0.8) +\dfrac{1}{2}\times (-9.8)(0.8)^2\\\Rightarrow 0.95=7\times \sin \theta (0.8) -3.136\\\Rightarrow 0.95=5.6\sin \theta -3.136\\\Rightarrow 5.6\sin \theta= 0.95+3.136\\\Rightarrow 5.6\sin \theta= 4.086\\\Rightarrow \sin \theta= \dfrac{4.086}{5.6}\\\Rightarrow \sin \theta=0.729\\\Rightarrow \theta=\sin^{-1}(0.729)\\\Rightarrow \theta=46.86^\circ[/tex]

Hence, the angle of the shoot of the basket ball with the horizontal is [tex]46.86^\circ[/tex] such that it reaches the hoop on time.

Part (2):

For this part, a diagram has been attached.

Two concentric current loops lie in the same plane. The smaller loop has a radius of 3.6 cm and a current of 12 A. The bigger loop has a current of 20 A . The magnetic field at the center of the loops is found to be zero. What is the radius of the bigger loop?

Answers

Answer:

the radius of bigger loop = 6 cm

Explanation:

given,

two concentric current loops

smaller loop radius = 3.6 cm

]current in smaller loop = 12 A

current in the bigger loop = 20 A

magnetic field at the center of loop = 0

Radius of the bigger loop = ?

[tex]B_t = B_1 + B_2[/tex]

[tex]0 = \dfrac{\mu_0I_1}{2R_1} +\dfrac{\mu_0I_2}{2R_2}[/tex]

now, on solving

[tex]\dfrac{I_1}{R_1} = \dfrac{I_2}{R_2}[/tex]

[tex]R_2 = I_2\dfrac{R_1}{I_1}[/tex]

       = [tex]20\times \dfrac{3.6}{12}[/tex]

       = 6 cm

hence, the radius of bigger loop = 6 cm

Bill steps off a 3.0-m-high diving board and drops to the water below. At the same time, Ted jumps upward with a speed of 4.2 m/s from a 1.0-m-high diving board. Choosing the origin to be at the water's surface, and upward to be the positive x direction, write x-versus-t equations of motion for both Bill and Ted.

Answers

Answer:

equation of  motion for Bill is

[tex]y(t) = 4.9t^2[/tex]

equation of  motion for Ted is

[tex]y(t) = 2 + (-4.2)(t) + 4.9t^2[/tex]

Explanation:

Taking downward position positive and upward position negative

g = 9.8 m/s^2

equation of  motion for Bill is

[tex]y(t) = y_0 +v_0 t +\frac{1}{2}gt^2[/tex]

[tex]y(t) = 0 + 0(t) +\frac{1}{2}gt^2[/tex]

[tex]y(t) = \frac{1}{2}\times (9.8t)^2[/tex]

[tex]y(t) = 4.9t^2[/tex]

equation of  motion for Ted is

[tex]y_0 = 2m -1m = 2m[/tex]

[tex]y_0 = -4.2 m/s[/tex]

[tex]y(t) = y_0 +v_0 t +\frac{1}{2}gt^2[/tex]

[tex]y(t) = 2 + (-4.2)(t) +\frac{1}{2}gt^2[/tex]

[tex]y(t) = 2 + (-4.2)(t) +\frac{1}{2}\times (9.8t)^2[/tex]

[tex]y(t) = 2 + (-4.2)(t) + 4.9t^2[/tex]

Answer:

Answer:

For Bill:

[tex]x(t)=3-(4.9*t^{2})[/tex]

For Ted:

[tex]x(t)=1+(4.2*t)+(-4.9*t^{2} )[/tex]

Explanation:

For Bill:

[tex]Initial position=x_{0}=3[/tex]

[tex]Initial velocity=v_{0}=0[/tex]

Now using [tex]2^{nd}[/tex] equation of motion,we have

[tex]x-x_{0}=(v_{0} *t)+(1/2*g*t^{2})[/tex]

[tex]x_{0} =3[/tex]  ,[tex]v_{0}=0[/tex]

Thus,equation becomes

[tex]x-3=1/2*g*t^{2}[/tex]

[tex]x=3+(0.5*g*t^{2})[/tex]

Taking acceleration upward positive and downward negative.

[tex]g=-10[/tex] [tex]m/s^{2}[/tex]

[tex]x(t)=3-4.9*t^{2}[/tex]    for bill

For Ted

[tex]x_{0} =1[/tex]

[tex]v_{0}=4.2[/tex] [tex]m/s[/tex]

Using the same equation

[tex]x-x_{0}=(v_{0} *t)+(1/2*g*t^{2})[/tex]

[tex]x_{0}=1[/tex] [tex]m[/tex]

[tex]v_{0}=4.2[/tex] [tex]m/s[/tex]

Substitute values

[tex]x-1=(4.2*t)+(1/2*g*t^{2})[/tex]

[tex]g=-10[/tex] [tex]m/s^{2}[/tex]

Thus equation becomes

[tex]x(t)=1+(4.2*t)+(-4.9*t^{2})[/tex]   for Ted

A 12 volt battery in a motor vehicle is capable of supplying the starter motor with 150 A. It is noticed that the terminal voltage of the battery drops to 10 V when the engine is cranked over with the starter motor. Determine the internal resistance of the 12 volt battery.

Answers

Answer:

[tex]r=\frac{1}{75}[/tex] Ω≈0.01333Ω

Explanation:

You can check the internal resistance model in the image I attached you.

Now using Kirchhoff's voltage law:

ε=[tex]Ir+IR[/tex]  (1)

Where:

[tex]IR=V_R=LoadVoltage=10V[/tex]

ε=12V

[tex]I=150A[/tex]

Evaluating the data provide in (1)

[tex]r=\frac{12-10}{150} =\frac{1}{75}[/tex]≈0.01333Ω

A ball is thrown upward. It leaves the hand with a velocity of 14.6 m/s, having been accelerated through a distance of 0.505 m. Compute the ball's upward acceleration, assuming it to be constant.

Answers

Answer:

upward acceleration is 211.04 m/s²

Explanation:

given data

velocity = 14.6 m/s

distance = 0.505 m

to find out

upward acceleration

solution

we have given distance and velocity and ball is going upward

so acceleration will be calculated by  velocity formula that is

v² - u² = 2×a×s   ............1

here v is velocity and u is initial velocity and s is distance and a is acceleration

and u = o because starting velocity zero

put here all there value in equation 1

v² - u² = 2×a×s

14.6² - 0 = 2×a×0.505

solve it we get a

a = 211.04

so upward acceleration is 211.04 m/s²

A fighterjet is launched from an aircraft carrier with the
aidof its own engines and a steam powered catapult. The thurst of
itsengine2.3*10^5N. In being launched from rest it moves through
adistance 87m and has KE 4.5*10^7J at lift off.What is the work
doneon the jet by the catapult.

Answers

Answer:

The work done on the jet is [tex]W_{jet} = 2.49\times 10^{7} J[/tex]

Given:

Force, F = [tex]2.3\times 10^{5} N[/tex]

Distance moved by the jet, x = 87 m

Kinetic Energy, KE = [tex]4.5\times 10^{7} J[/tex]

Solution:

Now, to calculate the work done on the fire fighter jet by the catapult, we find the difference between the KE of the jet at lift off and the work done by the engines.

This difference provides the amount of work done on the jet and is given by:

[tex]W_{jet} = KE - W_{engines}[/tex]              (1)

Now, the work done by the engines is given by:

[tex]W_{engines} = Fx = 2.3\times 10^{5}\times 87 = 2.001\times 10^{7} J[/tex]

Now, using eqn (1):

[tex]W_{jet} = 4.5\times 10^{7} - 2.001\times 10^{7} = 2.49\times 10^{7} J[/tex]

The sound of one student typing furiously on their History paper which is due at 8:00 am tomorrow morning is 60.0 dB. What will the decibel level be when three sleep deprived students are typing furiously in the same room?

Answers

Answer:

The the decibel level be when three sleep deprived students are typing furiously in the same room is 64.77 dB.

Explanation:

Given that,

Decibel level = 60.0 dB

Using formula of decibel level

[tex]\beta= 10 log\dfrac{I}{I_{0}}[/tex]

For one student,

[tex]60.0=10 log\dfrac{I}{I_{0}}[/tex]

For 3 students,

[tex]\beta'=10 log\dfrac{3I}{I_{0}}[/tex]

[tex]\beta'=10log 3+10 log\dfrac{I}{I_{0}}[/tex]

[tex]\beta'=4.77+60.0[/tex]

[tex]beta'=64.77\ dB[/tex]

Hence, The the decibel level be when three sleep deprived students are typing furiously in the same room is 64.77 dB.

The water behind Grand Coulee Dam is 1000 m wide and 200 m deep. Find the hydrostatic force on the back of the dam. (Hint: the total force = average pressure × area)

Answers

Answer:

The hydro static force on the back of the dam is [tex]1.96\times10^{11}\ N[/tex]

Explanation:

Given that,

Width b= 1000 m

Depth d= 200 m

We need to calculate the average pressure

Using formula of  average pressure

[tex]P_{avg}=\rho\times g\times d_{avg}[/tex]

Put the value into the formula

[tex]P_{avg}=1000\times9.8\times100[/tex]

[tex]P_{avg}=980000\ Pa[/tex]

We need to calculate  the hydro static force on the back of the dam

Using formula of force

[tex]F = P_{avg}\times A[/tex]

Put the value into the formula

[tex]F = 980000\times1000\times200[/tex]

[tex]F=1.96\times10^{11}\ N[/tex]

Hence, The hydro static force on the back of the dam is [tex]1.96\times10^{11}\ N[/tex]

A 2000-lb car drives from Denver (altitude: 5280 feet) to Los Angeles (sea level). What is its change in potential energy, in BTU? g = 32.174 ft/s² Provide your answer rounded to one decimal place, and make sure to include units. *

2) The velocity of an object increases by 50% (V₂=1.5 V₁). By what factor does the kinetic energy increase? *
1
4
1.5
2.25

Answers

Answer:

1) -13570.3 Btu

2) 2.25

Explanation:

The formula for potential energy is:

[tex]E_p = m*g*h[/tex]

Where m is the mass in slugs, g is the gravity and h is the change in height. Soliving the equation:

[tex]E_p = 2000lb*\frac{1 slug}{32.174 lb} *32.174 \frac{ft}{s^2} *(0ft-5280ft) = -10560000 lbf*ft * \frac{1 Btu}{778.17 lbf*ft} = -13570.3 Btu[/tex]

The car would lose -13570.3 Btu in potential energy.

2) The kinetic energy is given by:

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

Then:

[tex]\frac{E_k_2}{E_k_1} = \frac{\frac{1}{2}mv_2^2}{\frac{1}{2}mv_1^2}  = \frac{\frac{1}{2}m(1.5v_1)^2}{\frac{1}{2}mv_1^2}=1.5^2\frac{v_1^2}{v_1^2} = 2.25[/tex]

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