Given that r is a vector 125 km due north, and s is a vector 164 km due south, what are the
hr
magnitude and direction of the sum r + s?

Answers

Answer 1

Answer:

39 km due south

Step-by-step explanation:

Since the two vector have opposite directions, their sum will be the difference of magnitudes:

r + s = 164 - 125 = 39

And the direction is the same with the vector with greater magnitude, so it is south.

Answer 2

Answer:

Magnitude = 39 km

Direction = South

Step-by-step explanation:

Formula we use,

→ r + s

Now the required answer will be,

→ r + s

→ 164 + (-125)

→ 164 - 125

→ 39 km

Thus, answer is 39 km due south.


Related Questions

Question 6(Multiple Choice Worth 1 points)
(05.07 MC)
A scatter plot is made to model the amount of money left to pay on a car loan. The data used for the scatter plot are shown in the table:
Number of Months 3
Money Owed $19,500 $18,500 $21,500 $20,000 $22,000 $19,000
5
1
What does the y-intercept of the model represent?
O The monthly payments
The original amount of the loan
2
O The number of months it takes to pay off the loan
The amount of the loan that has been paid that month
0
4

Answers

Correct option is third option - " the original amount of the loan "

What is linear equation ? A linear equation, a first-order polynomial, that  is, H. The sum of a series of terms, each of which is the product of a constant and a variable to the first power, equals the constant. In particular, linear equations in n variables have the form a0 + a1x1 + ... + anxn = c. where x1,...,xn are variables,  coefficients a0,...,an are constants, and c is a constant. With multiple variables, the equation may be linear in some variables and non-linear in  others. So the equation x + y = 3 is linear in both x and y, but x + y2 = 0 is linear in x but not in y. An equation of two  linear variables represents a straight line in Cartesian coordinates. If the constant term c = 0, the line passes through the origin. A linear equation is an algebraic equation of the form y=mx+b. The above is sometimes called a "linear equation in two variables" where y and x are  variables.Calculation

x value would be the time in months and y value would be the loan amount that is left.

The y-intercept is basically the point where x is 0. So, we can say the y-intercept would be when time is 0.

That's basically when the loan started and the y-value represents the full loan amount., which is $22,000.

correct option is third option -- "the original amount of the loan".

learn more about linear equation here :
brainly.com/question/11897796

#SPJ1

The rise and run of the line, state the slope in simplest form

Answers

Answer:

it is called horizon simple question simple answer

Carlos paid $150.95 for Luxury Vinyl Flooring for his Family Room
which is 121 Square feet. He purchased a 1 square foot sample at Lowes to take home to see if the flooring will match his fireplace
in the Family room.

Based on this price, what is the cost of the
sample?

$1.25

$0.95

$1.00

$1.20

Answers

Step-by-step explanation:

121 ft² cost $150.95

1 ft² costs then 150.95/121 = $1.247520661... ≈

≈ $1.25

1. Which of the following numbers has factors that
include the smallest factor (other than 1) of 111?
A. 15
B. 22
C. 28
D. 40

Answers

The smallest factor (other than 1) of 111 would be 15.

Option (A) is correct.

What is the smallest factor of a number other than 1?

A number can have a maximum of one factor, and only one has that many factors. Every other number has more than one factor.

Prime numbers have two factors, for example, 2,3,5,7,11...,2729...,2927, 9999959999, and so on. Prime numbers have only one factor the number itself.

The factors of 111 are 1, 3, 37, and 111.

for option (A), the factors of 15 are 1, 3, 5, and 15.

for option (B), the factors of 22 are 1, 2, 11, and 22.

for option (C), the factors of 28 are 1, 2, 4, 7, 14, and 28.

for option (D), the factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40.

So if you observe all the options, the smallest factor (other than 1) of 111 would be 15.

Hence, the smallest factor (other than 1) of 111 would be 15.

To learn more about the factors of a number, visit:

https://brainly.com/question/18187355

#SPJ1  

The Serenity and the Mystic are sail boats. The Serenity and the Mystic start at the same point and travel away from each other in opposite directions. The Serenity travels at 16 mph and the Mystic travels at 20 mph. How far apart will they be in 2 hours?

Answers

After 2 hours Serenity and Mystic will be 72 miles apart

The speed of the Serenity  = 16 mph

The time taken = 2 hours

The speed = Distance / Time

The distance = The speed × time

The total distance traveled = 16 × 2

= 32 miles

The speed of the Mystic  = 20 mph

The time taken = 2 hours

The distance = The speed × time

Total distance traveled = 20 × 2

= 40 miles

Total distance = 32 + 40

= 72 miles

Hence, after 2 hours Serenity and Mystic will be 72 miles apart

Learn more about speed here

brainly.com/question/12759408

#SPJ9

Which expression is equivalent to 5m - (2m - 8) + 12 + 6m?

Answers

[tex]=5m-2m+8+12+6m\\=5m-2m+6m+8+12\\=3m+6m+20\\=9m+20[/tex]

The answer is 9m+20,it is equivalent to the expression in the question.

sara takes wedding pictures. for each picture, she has 1/4 chance that everyone looks at the camera. how many pictures must she take to have at least a 4/5 chance of having a picture in which everyone is looking at the camera?

Answers

For at least 6 pictures she must take to have at least a 4/5 chance of having a picture in which everyone is looking at the camera.

Let p define the probability of success in a Bernoulli trial, and P define the probability Sara wants to reach "at least" and n be defined as the number of trials. Then,

= 1 - (1 - p)ⁿ ≥ P

= (1 - p)ⁿ ≤ 1 - P

= n ≥ ln(1-P)/ln(1-p)

= n ≥ ln (0.2) / ln (0.75)

=5.6

Hence for at least n=6 photos, there is at least a chance of 4/5 that everyone is looking at the camera.

To learn more about probability and its theorem,

https://brainly.com/question/24232842

#SPJ4

What is the length of segment DE?

Answers

[tex]~~~~~~~~~~~~\textit{distance between 2 points} \\\\ D(\stackrel{x_1}{a}~,~\stackrel{y_1}{-2b})\qquad E(\stackrel{x_2}{4a}~,~\stackrel{y_2}{0})\qquad \qquad d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2} \\\\\\ DE=\sqrt{(4a-a)^2+( ~~ 0-(-2b)~~)^2}\implies DE=\sqrt{(3a)^2+(2b)^2}[/tex]

a simple random sample of 40 items resulted in a sample mean of 25. the population standard deviation is 5. what is the standard error of the mean? (round your answer to two decimal places).

Answers

The standard error of the mean is approximately 0.79 (rounded to two decimal places).

Define standard error ?

The standard error is a statistical term that measures the variability of a sample mean or an estimate of a population parameter from its true value. It is the standard deviation of the sampling distribution of the mean. In simpler terms, the standard error measures how much the sample mean varies from the true population mean. A smaller standard error indicates that the sample mean is more likely to be representative of the population mean, while a larger standard error suggests that the sample mean may not be as reliable.

The formula for the standard error of the mean is:

[tex]SE = \frac{\sigma }{\sqrt{n}}[/tex]

Where σ is the population standard deviation and n is the sample size.

Substituting the given values:

[tex]SE =\frac{5}{\sqrt{40}}[/tex]

SE ≈ 0.79

Therefore, the standard error of the mean is approximately 0.79 (rounded to two decimal places).

To learn more about standard deviation from the given link :

https://brainly.com/question/23907081

#SPJ1

PLEASE HELP

i already know that
-8 is wrong

Answers

Answer:

-16

Step-by-step explanation:

slope formula: y2-y1/x2-x1

y-16/17+19

y-16/36

Numerator is supposed to equal -32 since denominator is 36

y-16=-32

 +16.  +16

y=-16

Hopes this helps,please mark brainliest

Answer:

  (b)  -16

Step-by-step explanation:

You want the y-value that goes with x=17 on the line with slope -8/9 through point (-19, 16).

Point-slope equation

The point-slope form of the equation for a line is ...

  y -k = m(x -h) . . . . . . line with slope m through point (h, k)

The line with slope -8/9 through point (-19, 16) will have the equation ...

  y -16 = -8/9(x +19)

Y for x=17

You want the value of y for x=17. We can find that by substituting x=17 into the above equation:

  y -16 = -8/9(17 +19) = -8/9(36) = -32

Adding 16 gives the value of y:

  y = 16 -32 = -16

The line passes through the points (-19, 16) and (17, -16).

can someone please help me:)?

Answers

Equation A. (8(4+x) = 72, and answer C are your responses (5 hours).

What do babysitters for young children go by?

Caregiver, governess, nanny, au pair, infant-care employee, day-care provider, mother's assistant, and mother or father are a few alternative terms for babysitters that seem more professional.

How old do you need to be to watch children?

While most babysitters begin their careers between the ages of 11 and 14, there is no set legal minimum age requirement in most places. At age eleven, you could start a red cross babysitting route. You are old enough if your parents still remember you and think you are trustworthy enough to

Find out how much of her Friday's earnings was left over. four*8= 32

She has 72 dollars in total, of which 32 dollars were earned on Friday; the remaining 56 dollars were earned on Saturday. 72-32 equals forty.

She made 40 dollars on Saturday at an hourly rate of $8, so you divide 40 by 8 to get 5, and so on. On Saturday, she worked for five hours.

Learn more about babysitting here:

brainly.com/question/14821752

#SPJ1

6,311
✕ 41 pls answer

Answers

Answer:

258751

Step-by-step explanation:

multiply and you'll get the answer

What is the value of x in the equation-2/9x=2/5?

A. -1 4/5

B. -5/9

C. 5/9

D. 1 4/5

Answers

The value of x is -1 4/5 i.e, Therefore, the correct option is A

Define Algebraic Expression

The concept of algebraic expressions is the use of letters or alphabets to represent numbers without providing their precise values. We learned how to express an unknown value using letters like x, y, and z in the fundamentals of algebra. Here, we refer to these letters as variables. Variables and constants can both be used in an algebraic expression. A coefficient is any value that is added before a variable and then multiplied by it. In mathematics, an expression that incorporates variables, constants, and algebraic operations is known as an algebraic expression (addition, subtraction, etc.).

Given expression,

-2/9 x=2/5

Isolate the variable, x

x = (2 * 9) / ( 5 * -2)

x = - (9/5) or -1 4/5

Hence, the value of x is -1 4/5 i.e, option(A)

To read more about Algebraic Expression.

https://brainly.com/question/25678139

#SPJ9

examples of one solution

Answers

Answer:I can’t see image on mobile

Step-by-step explanation:

h

um so like hii,, not school related or anyrhing but ill just like to ask anyone if they know the reason why ur phone (samsung) like randomly delted ur music and photos. yah and ill like to know how u could resolve that from happening again​

Answers

Answer: Can you check the "Recently Deleted" folder? You may find this in the "My Files" app. If this does not work, and you can confirm you have no backups whatsoever, then your photos are as good as gone. This has happened to Android devices in the past (or Samsung devices mostly) where all their media would just disappear. As far as I know, all Samsung themselves say is to restart your phone to try your luck. An app crashing or some form of corrupt media may have caused your photos to go missing. There may, however, still be a small chance that the photos are there, somewhere on your phone, you just can't find them. I advise checking the storage in "Device Care" and see if the Gallery app is using much storage. If it is, I would connect it to a PC and look through the files again.

Step-by-step explanation:

The person is correct good job!!!!!?

what is the inequality

Answers

Answer:-4<x<=5

Step-by-step explanation:

The white dot is above -4 and the filled in dot is above 5. Put that together plus the correct inequality signs and you get -4<x<=5

Answer: [tex]-4 < x\leq 5[/tex]

Step-by-step explanation:

The inequality ends at 4 and it is colored white so x must be greater than -4 therefore the first expression is x > -4 or -4 < x.

The other side of the inequality ends at 5 and it's colored black so x is less than or equal to 5. Therefore the second expression is [tex]x\leq 5[/tex].

if we merge the two equations together than we would get [tex]-4 < x\leq 5[/tex].

I hope that helped you.

:)

what do integers added or subtracted from the function do to the graph?

Answers

The addition or subtraction of a constant to a function will change its position in the cartesian plane. Depending on the sign of the constant, it can shift upwards or downwards.

Let a quadratic function be f(x) = 2x^2.

Let c be the positive constant.

It is now necessary to determine what will happen if we add or subtract a constant to the function.

The function f(x) = 2x^2 is a parabola opening upwards.

Now, if we add the positive constant c, then the graph of the function will shift upwards by c units and nothing will change. If we subtract the positive constant c, then the graph of the function will shift downwards by c units.

Thus, the addition or subtraction of a constant to a function will change its position in the cartesian plane. Depending on the sign of the constant, it can shift upwards or downwards.

To learn more about quadratic function visit:

https://brainly.com/question/28831746

#SPJ1

translate (1,-2) 4 left

Answers

The new coordinate after the translation of 4 point left is  (-3, -2)

Translation

Translation is done by moving the vertices of the figure the prescribed number of spaces on a coordinate plane and then drawing the new figure.

Given,

Here we have the points (1, -2).

Now, we have to translate this point by left side by 4 point.

In order to translate the given point we have to take the value of the x coordinate and then we have to subtract the translation point from it,

So, the calculation for this one is look like

Here the value of the x coordinate is 1

And now we have to subtract 4 from it,

So,

=> 1 - 4

=> -3

Therefore, the new coordinate after the translation is (-3, -2).

To know more about Translation here.

https://brainly.com/question/12463306

#SPJ1

Please solve the problem below
2(x+4)+2=5x+1

Answers

Answer:

3

Step-by-step explanation:

2x+8+2=5x+1

2x+10=5x+1

CLT

10-1=5x-2x

9=3x

9/3=3x/3

x=3

Answer:x=3

Step-by-step explanation:

Given,

2(x+4)+2=5X+1

solving the brackets,

2x+8+2=5x+1

2x+10=5x+1

taking the like terms together and solving them,

10-1=5x-2x

9=3x

x=9/3

x=3

For more reference on solving equations,

https://brainly.com/question/14132759

Please someone help me with this question my exams in a few days

Answers

Answer:

see explanation

Step-by-step explanation:

(i)

using Pythagoras' identity in the right triangle

the square on the hypotenuse is equal to the sum of the squares on the other 2 sides , that is

(k + x)² = m² + (k - x)² ← expand factors on both sides using FOIL

k² + 2kx + x² = m² + k² - 2kx + x² ( add 2kx to both sides )

k² + 4kx + x² = m² + k² + x² ( subtract k² + x² from both sides )

4kx = m² ( divide both sides by 4k )

x = [tex]\frac{m^2}{4k}[/tex]

----------------------------------------------------------

(ii)

the area A of a triangle is calculated as

A = [tex]\frac{1}{2}[/tex] bh ( b is the base and h the perpendicular height )

here b = m and h = k - x

A = [tex]\frac{1}{2}[/tex] m (k - x) ← substitute x = [tex]\frac{m^2}{4k}[/tex]

  = [tex]\frac{1}{2}[/tex] m ( k - [tex]\frac{m^2}{4k}[/tex] ) ← distribute parenthesis

  = [tex]\frac{mk}{2}[/tex] - [tex]\frac{m^3}{8k}[/tex]  ← express as a single fraction

  =  [tex]\frac{4mk^2-m^3}{8k}[/tex] ← factor out m from each term in the numerator

  = [tex]\frac{m(4k^2-m^2)}{8k}[/tex] ← factor (4k² - m² ) as a difference of squares

  = [tex]\frac{m(2k+m)(2k-m)}{8k}[/tex]

Answers ? Help pls ):

ONLY ANSWER IF YOU REALLY KNOW IT ! NO LINKS !

Answers

Answer:

Break even 126 units

105x - (90x + 1890)  Profits will be revenue minutes expenses.

The second answer.

Step-by-step explanation:

105x = 90x +1890  Subtract 90x from both sides

15x = 1890  Divide both sides by 15

x 126

They need to sell 126 units to break even.

105(91) -[90(91) + 1890]

9555-8190-1890

9555 - 16380

-6825

Selling 91 units will produce a loss of 6825

Please help me pleaseeee

Answers

The value of x for the given triangle is 2 units.

According to the question,

We have the following information:

We have a figure of triangle where a line segment is dividing the two sides. The measurement of some of its sides are given.

Now, the side with measurement 12 units and one divided side is 4 units.

The next side to 4 units in the same side will be (12-4) units or 8 units.

Now, using the basic proportionality theorem, we have the following expression:

6/6x = 4/8

Using the cross multiplication method:

6x*4 = 8*6

x = 48/24

x = 2 units

Hence, the value of x for the given triangle is 2.

To know more about value of x here

https://brainly.com/question/7537975

#SPJ1

x divided by 12; x= 2/3

Answers

Answer:

1/18

Step-by-step explanation:

Since x=2/3, we can plug in 2/3 for x, and we have 2/3 divided by 12.

Based on what we know about fractions, we can say that dividing by 12 is the same as multiplying by 1/12.

Therefore, we have the expression 2/3*1/12.

Next, we get 2/36, which can be simplified into 1/18.

A, B, C, D, E, F, G & H form a cuboid.
AB= 5.4 cm, BC = 3.4 cm & CG = 6.7 cm.
Find HC rounded to 1 DP.

Answers

Refer to the attachment for the diagram:

The length of HC rounded to 1 DP = 9.3 cm²

What is a cuboid?

A cuboid is a solid shape or a three-dimensional shape in geometry. A cuboid is a convex polyhedron that has eight vertices, twelve edges, and six rectangular faces. A rectangular prism is another name for a cuboid. A cube is an object with six square faces on a cuboid.

From the figure,

length (l)= 5.4 cm = AB

width (w)=3.4 cm = BC

height (h)= 6.7 cm = CG

Formula:

Length of diagonal = √(l²+w²+h²) = √(5.4²+3.4²+6.7²) = 9.25 cm²

Rounded to 1 decimal point:

9.3 cm²

To learn more about the cuboid from the given link

https://brainly.com/question/26403859

#SPJ1

I need help immediately!! It’s subtract mixed numbers with unlike denominators!!

Answers

Answer:

C

Step-by-step explanation:

A = 3 11/12

B = 3 2/3

C = 4 1/4

D = 3 3/4

4 1/4 is equivalent to 4 3/12.

HELP ASAP!!
Match each equation on the left to its solution on the right.
Some answer choices on the right will be used more than once.
2(6+4x)= 8x + 6
2(4x − 2) = 10x – 6
7+x=2x+6
2x+2=-2(1-x)
x = all real numbers
x = 1
no solution

Answers

Answer:

I believe that these are the answers.

Step-by-step explanation:

1. 2(6+4x)=8x+6    No Solution

2. 2(4x − 2) = 10x – 6  x=1

3. 7+x=2x+6    x=1

4. 2x+2=-2(1-x)   No Solution

Hope this helps

Answer:

Step-by-step explanation:

2(6 + 4x) = 8x + 6

12 + 8x = 8x +6

12 -6 + 8x = 8x + 6 -6

6 + 8x = 8x

6 + 8x - 8x = 8x -8x

6 = 0

no solution

2(4x -2) = 10x -6

8x -4 = 10x -6

8x - 4 +4 = 10x -6 +4

8x = 10x - 2

8x - 10x = 10x -10x -2

-2x = -2

-2x/-2 = -2 /-2

x = 1

7 + x = 2x +6

7 -6 + x = 2x +6 -6

1 + x = 2x

1 + x -x = 2x -x

1 = x

2x + 2 = 2(1 - x)

2x + 2 = 2 - 2x

2x +2 -2 = 2 -2 - 2x

2x = -2x

2x + 2x = -2x + 2x

4x = 0

4x/4 = 0/4

x = 0

I could not get x = all real numbers for any of the equations.

Which division setup matches this question? Dr. Bender feeds her dog ½ of a cup of dog food each day. How long will 5 ¾ cups of dog food last?

Answers

Answer:

5 days

Step-by-step explanation:

you need to make 5 3/4 into an improper fraction

(5x40)+3/4= 23/4

make all fractions have a common denominator

1/2 = 2/4    

you multiply numerator and denominator by 2 to get a denomintator of 4

23/4 ÷ 2/4

to divide a fraction you turn the second fraction into a reciprocal

2/4 in a reciprocal is 4/2

then you multiply the fractions together

23x2/2x4

simlplify to get

46/8 = 23/4

make into a mixed number by dividing by 4

5 3/4

Martin has $30 and he makes $10 an hour mowing grass. His friend has $60 and makes $7 an hour babysitting. After how many hours will Martin have more money?

Answers

Martin will have more-money than his friend after babysitting for 10 hours

How to determine the relationship equation?

The given parameters in the question are:

Martin

Initial amount = $30

Additional earnings = $10

His friend

Initial amount = $60

Additional earnings = $7

The equation that shows their total earnings is

y = Initial amount + Additional earnings * x

So, we have

Martins: y = 30 + 10x

His friend: y = 60 + 7x

When Martin has more money, we have

Martins > His friend

This gives

30 + 10x > 60 + 7x

Evaluate the like terms in the above inequality

3x > 30

Divide by 3

x > 10

Hence, Martin will have more money after 10 hours

Read more about linear equations at

https://brainly.com/question/14323743

#SPJ1

pamala's age is 2 * jiri's age the sum of their ages is 48 what is Jiri's age​

Answers

Answer:

16

Step-by-step explanation:

p = 2j

p+j = 48

2j + j = 48

3j = 48

3/3 j = 48/3

j = 16

Mario purchases a prepaid phone plan for 50$. Each minute he uses costs $0.13. How many minutes can Mario talk on this plan

Answers

Answer:

49.87

Step-by-step explanation:

He can talk on the phone for 385 minutes.
Other Questions
a researcher examining a root tip observes a plant cell with condensed sister chromatids, kinetochores with attached microtubules, and individual chromosomes that are aligned at the equatorial plate of the cell. which of the following best describes what the next process will be in the cell? responses homologous chromosomes (each with two sister chromatids) will move toward opposite poles of the cell. homologous chromosomes (each with two sister chromatids) will move toward opposite poles of the cell. paired chromatids will separate, and the new daughter chromosomes will move toward opposite poles of the cell. paired chromatids will separate, and the new daughter chromosomes will move toward opposite poles of the cell. the nuclear envelope will break down, and the spindle will begin to form. the nuclear envelope will break down, and the spindle will begin to form. the chromatin will decondense, and the daughter cell will enter interphase. Read this excerpt from a story and choose the title that best fits the focus ofthe narrative.Elton lived two houses away from Bob, an old man who would stand onhis porch and yell at Elton when he walked to school. One day, Bobwasn't there. Elton was relieved. But then Elton found out that Bob wassick, and his mom made him take Bob some flowers. When Bobrecovered, he said that Elton was the only one who came to visit. Fromthat day on, Bob smiled and waved at Elton. What might be their reasons for supporting the soda tax? democrates Help please, read the following in the picture Can someone please look in the photo and explain? Thanks so much I appreciate the help. What is the bond order of NO+ and NO-? How did Henry Cowell and John Cage experiment with new musical ideas throughout the 20th century? Be sure to accurately identify specific ways they experimented with harmony and rhythm. Name 3 pieces by these composers to prove your point and compare/contrast the two. At least 3 paragraphs will suffice miller corporation is considering replacing a machine. the replacement will reduce operating expenses by $20,000 per year for each of the five years the new machine is expected to last. although the old machine has zero book value, it can be used for five more years. the depreciable value of the new machine is $52,000. the firm will depreciate the machine using a straight line depreciation over five years. it has a 21% tax rate. calculate periodic cash flow in year 2. hint: first, calculate net earnings after tax, then calculate operating cash flows. What kind of change results from the breakdown of starch into glucose by saliva?. Which membrane protein allows water, but not solutes to diffuse across a lipid bilayer?. Define senescent. What cells put off senescence? solve 5x+y=24x+y=4 use the linear combination method rank the members of each compound in order of increasing ionic character of their bonds: sef4, tef4, brf3. arrange compounds as low ionic character < high ionic character. enter it like this (just an example - no spaces) se-f Given the polynomial f(x)= 2x^3-x^24x4, what i the mallet poitive integer a uch that the intermediate value theorem guarantee a zero exit between 0 and a ? Regional erosion occurs at a rate of 2 m per 1,000 years. How much regional erosion will occur over 1,000,000 years? responses 20 m 20 m 200 m 200 m 2,000 m 2,000 m 100,000 m. calculate country b's future gdp 8 years from now if the current gdp is $9,555 and the expected growth rate is 2%. round your answer to the nearest whole number. provide your answer below: sarah files her tax return with a long term capital loss of $20,000 and a short term capital gain of $15,000. she had only one w-2 with $18,000 earnings and one 1099-b from a brokerage. what is the amount of sarah's capital loss carryforward? Developing our constitution technician a says that bearings have a soft surface that flows away from high spots in case of a nick in the crankshaft. technician b says that dirt can be absorbed into the crank- shaft journal surface. who is right? according to research on marital satisfaction in couples with children, the shape of the marital satisfaction curve across time is