A particle moves along the x-axis so that at time t ≥ 0 its position is given by x(t) = 2t3 - 21t2 + 72t - 53. At what time t is the particle at rest?

Answers

Answer 1

Step-by-step explanation:

The particle is at rest when the derivative of x(t), which is its velocity, is zero, i.e.,

[tex]\dfrac{d}{dt}[x(t)] = \dot{x}(t) = 0[/tex]

Since [tex]x(t) = 2t^3 - 21t^2 + 72t - 53,[/tex] its derivative is

[tex]\dot{x}(t) = 6t^2 - 42t + 72[/tex]

Equating this to zero, we get

[tex]6t^2 - 42t + 72 = 0 \Rightarrow t^2 - 7t + 12 = 0[/tex]

This is a familiar quadratic equation whose roots are

[tex]t = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}[/tex]

[tex]\;\;\;= \dfrac{7 \pm \sqrt{(7)^2 - 4(1)(12)}}{2}[/tex]

[tex]\;\;\;= \dfrac{7 \pm 1}{2}[/tex]

[tex]\;\;\;= 3\;\text{and}\;4[/tex]

This means that the particle will be at rest at t = 3 and t= 4.


Related Questions

Which number is a perfect cube?
O4
O 16
O 24
O 64

Answers

64 is a good number for a cube

MATHH QUESTION HELP. mesasuremtns

Answers

Answer:

Step-by-step explanation:

Answer:

See image

Step-by-step explanation:

Look at the front side of the building. It's a triangle, with the height given. We can see a right triangle here which means we can use the Pythagorean theorem. a^2 + b^2 = c^2 (a and b are the shorter sides called legs and c is the longest side called the hypotenuse)

20^2 + 13^2 = c^2

400 + 169 = c^2

569 = c^2 square root both sides

Sqrt 569 is approximately 23.85 ft. This is the length from the roof peak down the front edge to the bottom front right corner in the image.

Now, if we consider the roof itself. That edge is now a leg (on the front face it was the hypotenuse). The other leg is the 35 ft width given. So we'll use pythagorean theorem again to find the diagonal

23.85^2 + 35^2 = c^2

568.8 + 1225 = c^2

1793.8 = c^2

Square root both sides of the equation.

Sqrt 1793.8 = c

42.35 ft = c

The diagonal of the roof is just over 42 feet, that is 42.35 feet.

if you are in a 200 meter race and finish 19 meters ahead of your opponent, if you were to run the race again, where woild you have to start to end the race in a tie?

Answers

Answer:

i haven't done this in years but i'm pretty sure -19 meters

Step-by-step explanation:

For which value of x is inequality 3(1+x)<+6true?

Answers

Answer: For in the inequality to be true, X must be less than or equal to 1. That represented as an in equality is X < 1.

x<1 true

Step-by-step explanation:

3(1+x)<+6= 3×1+3×X<+6=3+3x<6 then3x=6-3 solution 3x=3 devide by 3 both sides the answer is x=1 hence x<1 verified

In need of help pls. Try and answer asap.

Answers

Answer:

Step-by-step explanation:

∠1 and 85 are supplementary

m∠1 = 180 - 85 = 95°

Please help I don’t understand!!

Answers

Answer:

[tex] \frac{5(x + y)}{ - 8x} [/tex]

Step-by-step explanation:

quotient means division

numerator is the top

denominator is the bottom

product means multiply

sum means add

If 9 out of 20 candies are orange, how many orange candies will there be per 100 candies total?

Answers

Answer:

45

Step-by-step explanation:

20 / 9 = 2.222222222223

100 / 45 = 2.222222222223

9 is 45% of 20 and 45 is 45% of 100.

WILL GIVE BRAINLIEST!!!!

Answers

Answer:

$319

Step-by-step explanation:

Usually, sales tax is proportional to the amount of the sale, so if the sales tax is a factor of 22/16 times the original tax, then the sale amount must be 22/16 times the original item cost:

 (22/16)·$232 = $319

I need help solving please

Answers

Answer:

B.

Step-by-step explanation:

Range is all the set y values.

Answer:

See image

Step-by-step explanation:

The range is all of the y-values. Look at the points on the graph, and make a list of all the y's That will be the range.

the students in Jake's class , 6 have visited a zoo and 6 have visited a factory 3 students have visited both a zoo and a factory . How many students have visited a zoo but not a factory ?

Answers

Answer:

3

Step-by-step explanation:

6 have visited a zoo.

6 have visited a factory.

3 visited both.

Of the 6 who visited a zoo, 3 also visited a factory.

Of the 6 who visited a factory, 3 also visited a zoo.

Here is the list of students:

3 visited a zoo but not a factory.

3 visited a factory but not a zoo.

3 visited both.

Answer: 3

How much money will you spend on these items? Round to the nearest cent.
Shopping List:
2.75 pounds of grapes.
0.8 pounds of garlic
The grapes are $0.89 per pound.
The Garlic is $0.34 per pound. Please Help

Answers

Answer:

$2.72

Step-by-step explanation:

2.74x0.89=2.4475

0.8x0.34=0.272

2.447+0.272=2.719, rounded is 2.72

Which graph represents a function?

Answers

Answer:

just the first on. upper left corner

the circled one (the first one)
it goes through the center (0,0) and it’s a straight line.

You work for a consumer advocacy agency and want to estimate the populations means cost of monthly maintenance on a car. It is assumed that the average monthly cost of maintenance is $210 dollars. In a random sample of 100 cars, you find the average monthly maintenance cost was $185. Assume that the population standard deviation is known to be $125; Use a 0.03 significance level to test the claim that the population mean weight of cost of maintenance differs from 210 lbs. State the null and alternate hypothesis test


A) H0: μ≤185
Ha: μ>185

B) H0: μ≥210
Ha: μ<210

C) H0=210
Ha: μ=185

D) H0: μ=210
Ha: μ ≠ 210

Answers

According to the desired test, the hypothesis are given by:

D) H0: μ=210

Ha: μ ≠ 210

At the null hypothesis, it is tested if the population mean is of 210 lbs, that is:

[tex]H_0: \mu = 210[/tex]

At the alternative hypothesis, it is tested if the population mean differs from 210 lbs, that is:

[tex]H_a: \mu \neq 210[/tex]

Hence, the correct option is:

D) H0: μ=210

Ha: μ ≠ 210

A similar problem is given at https://brainly.com/question/25707631

I need to know the area of this triangle and I would like to have an explanation because I dont know how to do it I know the formula just not how to get the height

Answers

(-2,1)(4,3)(-2,-5)

Area

[tex]\\ \tt\longmapsto \dfrac{1}{2}|x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)|[/tex]

[tex]\\ \tt\longmapsto \dfrac{1}{2}|(-2)(3+5)+(4)(-5-1)+(-2)(1-3)|[/tex]

[tex]\\ \tt\longmapsto \dfrac{1}{2}|-16-24+4|[/tex]

[tex]\\ \tt\longmapsto \dfrac{1}{2}|-36|[/tex]

[tex]\\ \tt\longmapsto 18units^2[/tex]

Find the slope of a line paprallel to the line below

Answers

Answer is -1/2

Parallel lines both have the same gradient or slope

So the line parallel to the one in the diagram will have the same gradient, just that they will have different y-intercepts.

The equation of the blue line is y=-x+ 5. Manipulate the orange line by setting the sliders so its slope, m, is -1 and its y-intercept, b, is 5. Which statement describes the system after the changes? O The lines intersect at the same point as before the changes. O The lines intersect at a different point than before the changes. O The lines do not intersect. 0 The lines overlap.

Answers

I think it would be the first one because the y intercept is the same so that point doesn’t change, but if it includes the x axis then it would be the second one- you could also say that they overlap because they cross over each-other
Hope that helps :)

Answer:

D

Step-by-step explanation:

Tina wants to sew a piece of fabric into a scarf in the shape of an isosceles triangle as shown in the accompanying diagram what are the values of x and y ?

Answers

Answer:

A. x = 96 and y = 42

Step-by-step explanation:

The required measure of the angle x and y is given as x =92° and y = 42°. Option A is correct.

Given that,
Tina wants to sew a piece of fabric into a scarf in the shape of an isosceles triangle as shown in the accompanying diagram what are the values of x and y is to be determined.

What is the isosceles triangle?

A triangle with two sides and two congruent angles that are equal each other is called an isosceles triangle.

Here,
For an isosceles triangle,
The measure of the angle opposite to the equal side is equal, So
y = 42°

Now,
The sum of the angles in the triangle° is equal to 180,
x + y + 42 = 180
x + 42 + 42 = 180
x = 96

Thus, the required measure of the angle x and y is given as x =92° and y = 42°. Option A is correct.

Learn more about the isosceles triangle here: https://brainly.com/question/2456591

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General admission to the fair is $8.00, and rides cost $3.00 each.

Answers

What is the equation?

Answer:

$24.00

Step-by-step explanation:

8x3=24

I need help asap! Pls :)

Answers

Answer:

Step-by-step explanation:

6x + 10 + 2x + 26 = 180

8x + 36 = 180

8x = 144

x = 18

I’ll give brainliest to the person who give me the correct answer and pointsss.
Match them

Answers

I think the y=ab^x goes with the first graph and the y=logbc goes with the second

Step-by-step explanation:

pictures

Expand and simplify: (x - 7)(x+7)

Answers

Answer:

[tex]x^{2} -49[/tex]

Step-by-step explanation:

Answer:

[tex](x-7)(x+7) =x^2 -7^2 = x^2 -49[/tex]

Step-by-step explanation:

A=1/2h(b1+b2) is the formula for the area of a trapezoid. Rewrite the formula for h, and then find the height of the trapezoid that has an area of 78 square inches and base lengths of 5 inches and 8 inches.

Answers

Answer:

Let's neaten up that equation a bit:

trapezoid area = height * (sum of the bases) / 2

height = 2 * area / (short base + long base)

height = 2 * 78 / (5 + 8)

height = 156 / 13

height = 12 inches

Source: https://www.1728.org/quadtrap.htm

Step-by-step explanation:

The formula for the height is h = (b1+b2)/2A and the height of the trapezoid is 12 inches

What is area of a trapezoid?

A trapezoid, also known as a trapezium, is a flat closed shape having 4 straight sides, with one pair of parallel sides.

The area of a trapezoid is expressed as;

A = 1/2( a +b) h

where a and b are the parallel sides and h is the height.

Making h the subject

(a+b)h = 2A

h = 2A/( a+b)

h = 2A( b1 + b2)

A = 78 in²

a = 5 in

b = 8 in

h = 2 × 78/( 8+5)

h = 156/13

h = 12 in

learn more about area of trapezoid from

https://brainly.com/question/1410008

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What property is used to rewrite (x + 2)(y + z) as y (x + 2) + z (x + 2)

Answers

Answer:

Distributive Property

Step-by-step explanation (if you were to show the steps):

(x+2)(y+z)   (first expression)

xy + xz + 2y + 2z (Distributive Property of Multiplication)

yx + 2y + zx + 2z (use the Commutative Property of Addition and Commutative Property of Multiplication to group xy (also known as yx) and 2y together, and to group xz (also known as zx) and 2z together)

y(x + 2) + z(x + 2) (use factoring to get the rewritten expression at the end)

Compute the area of a circle with a diameter of 18 inches.

Answers

Answer:

254.34

Step-by-step explanation:

Diameter: 2×radius

Radius:Diameter÷2

Area: pi×radius²

18/2=9

Radius=9

pi=3.14

3.14×9²=254.34

The area is 254.34

can someone plz help with this FAST
I WILL MARK BRAINLIEST

Answers

Answer:

Maria

Step-by-step explanation:

Sean - 2 minutes (1 mile/minute)

Maria - 4 minutes (0.5 miles/minute)

David - 3 minutes (1 mile/minute)

Carrie - 2 minutes (0.5 miles/minute)

Will give brainliest

Answers

Answer:

between midnight and 3am i think

Step-by-step explanation:

51.33333333 just round it plz

Answers

Answer:

51

Step-by-step explanation:

The answer would be 51 because the numbers behind the decimal are below 5

Answer:

51

Step-by-step explanation:

51.33333333 rounds to 51 because 3 is less than 5.

When rounding, always look at the number before the first number in front of the decimal. If it is more than 5, round up. If it is less than, round down.

the questions are in the pdfs i really need help

Answers

Answer:

Step-by-step explanation:

1) 11 + 11

2) 17 - n

3) x^2

4) 3^3

5) 88 / 8

6) 6 + 11

7) the quotient of 35 and 5

8) the sum of 4 and 5

9) 10 squared

10) 3 less than x

13) p^3 + qp

2^3 + 4(2)

8 + 8 + 16

14) (y^3)z / 3

(5^3)3 / 3

125(3) / 3

375 / 3

125

15) 2 + (j - h)^2

2 + (5 - 3)^2

2 + (2)^2

2 + 4

6

A school has 2880 students. The following information refers to the students:
7/20 are freshmen, 2/9 are juniors, 1/6 are seniors. What fractional part are sophomores?
How many students are sophomores?

Answers

Answer:

752

Step-by-step explanation:

7/20 of 2880 = 1008

2/9 of 2880 = 640

1/6 of 2880 = 480

2880 - 1008 - 640 - 480 = 752

What is the equation of the line that passes through the point (8,-4) and has a slope of 1/2

Answers

Answer:

y = 1/2x - 8

Step-by-step explanation:

Assuming that they want the equation in slope intercept form we would use the following form: y = mx + b

where m = slope and b = y intercept.

We are given the slope and a point on the line. We need to find the y intercept. We can do this by plugging in what we are given and then solving for b.

y = mx + b

slope (m) = 1/2

x value of given point (x) = 8

y value of given point (y) = -4

- plug in these values -

-4 = (1/2)(8) + b

now solve for b

multiply 1/2 and 8

-4 = 4 + b

subtract 4 from both sides

-8 = b

So the y intercept (b) is -8

We now plug in the slope and y intercept into slope intercept form

y = mx + b

m = 1/2 and b = -8

y = 1/2x - 8 is the equation of the line that passes through the point (8,-4) and has a slope of 1/2

For more validation refer to the attached image.

[tex]\text{Given that,}\\\\(x_1,y_1) = (8,-4), ~~ \text{and slope, m} = \dfrac 12\\\\\text{Equation with given points,}\\\\y -y_1 = m(x-x_1)\\\\\implies y -(-4) = \dfrac 12 (x-8)\\\\\implies y+4 = \dfrac 12 x - 4\\\\\implies y= \dfrac 12x -4 -4 \\\\\implies y = \dfrac 12 x -8\\\\\implies y = \dfrac{x-16}2\\\\\implies 2y = x -16\\\\\implies x -2y = 16[/tex]

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