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3 years ago

the diameter of a cylindrical construction pipe is 4 ft. if the pipe is 19 ft long, what s it’s volume?

Mathematics

1 answer:

choli [55]3 years ago

3 0

Answer:

76 $\pi$ or 238.76 $units^{3}$

Step-by-step explanation:

The volume of a cylinder is V = $\pi r^{2} h$

Here the radius is r = $\frac{1}{2} d$ = $\frac{1}{2}(4)=2$

The height is given as 19 ft

Then plug in all the numbers into the equation

V = $\pi (2^{2})(19) = 76\pi = 238.76 units^{3}$

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Can someone please help me with this

Mama L [17]

Answer:

27.

Equation of 2 tangent lines at the given curve going through point P is:

y = -7x + 1

y = x + 1

28.

Part 1: 400 feet

Part 2: Velocity is +96 feet/second (or 96 feet/second UPWARD) & Speed is 96 feet per second

Part 3: acceleration at any time t is -32 feet/second squared

Part 4: t = 10 seconds

29.

Part 1: Average Rate of Change = -15

Part 2: The instantaneous rate of change at x = 2 is -8 & at x = 3 is -23

Step-by-step explanation:

27.

First of all, the equation of tangent line is given by:

$y-y_1=m(x-x_1)$

Where m is the slope, or the derivative of the function

Now,

If we take a point x, the corresponding y point would be $x^2-3x+5$ , so the point would be $(x,x^2-3x+5)$

Also, the derivative is:

$f(x)=x^2-3x+5\\f'(x)=2x-3$

Hence, we can equate the DERIVATIVE (slope) and the slope expression through the point given (0,1) and the point we found $(x,x^2-3x+5)$

The slope is $\frac{y_2-y_1}{x_2-x_1}$

So we have:

$\frac{x^2-3x+5-1}{x-0}\\=\frac{x^2-3x+4}{x}$

Now, we equate:

$2x-3=\frac{x^2-3x+4}{x}$

We need to solve this for x. Shown below:

$2x-3=\frac{x^2-3x+4}{x}\\x(2x-3)=x^2-3x+4\\2x^2-3x=x^2-3x+4\\x^2=4\\x=-2,2$

So, this is the x values of the point of tangency. We evaluate the derivative at these 2 points, respectively.

$f'(x)=2x-3\\f'(-2)=2(-2)-3=-7\\f'(2)=2(2)-3=1$

Now, we find 2 equations of tangent lines through the point (0,1) and with respective slopes of -7 and 1. Shown below:

$y-y_1=m(x-x_1)\\y-1=-7(x-0)\\y-1=-7x\\y=-7x+1$

and

$y-y_1=m(x-x_1)\\y-1=1(x-0)\\y-1=x\\y=x+1$

So equation of 2 tangent lines at the given curve going through point P is:

y = -7x + 1

y = x + 1

28.

Part 1:

The highest point is basically the maximum value of the position function. To get maximum, we differentiate and set it equal to 0. Let's do this:

$s(t)=160t-16t^2\\s'(t)=160-32t\\s'(t)=0\\160-32t=0\\32t=160\\t=\frac{160}{32}\\t=5$

So, at t = 5, it reaches max height. We plug in t = 5 into position equation to find max height:

$s(t)=160t-16t^2\\s(5)=160(5)-16(5^2)\\=400$

max height = 400 feet

Part 2:

Velocity is speed, but with direction.

We also know the position function differentiated, is the velocity function.

Let's first find time(s) when position is at 256 feet. So we set position function to 256 and find t:

$s(t)=160t-16t^2\\256=160t-16t^2\\16t^2-160t+256=0\\t^2-10t+16=0\\(t-2)(t-8)=0\\t=2,8$

At t = 2, the velocity is:

$s'(t)=v(t)=160-32t\\v(2)=160-32(2)\\v(2)=96$

It is going UPWARD at this point, so the velocity is +96 feet/second or 96 feet/second going UPWARD

The corresponding speed (without +, -, direction) is simply 96 feet/second

Part 3:

We know the acceleration is the differentiation of the velocity function. let's find it:

$v(t)=160-32t\\v'(t)=a(t)=-32$

hence, the acceleration at any time t is -32 feet/second squared

Part 4:

The rock hits the ground when the position is 0 (at ground). So we equate the position function, s(t), to 0 and find time when it hits the ground. Shown below:

$s(t)=160t-16t^2\\0=160t-16t^2\\16t^2-160t=0\\16t(t-10)=0\\t=0,10$

We disregard t = 0 because that's basically starting. So we take t = 10 seconds as our answer and we know rock hits the ground at t = 10 seconds.

29.

Part 1:

The average rate of change is basically the slope, which is

Slope = Change in y/ Change in x

The x values are given, from 2 to 3, and we need to find corresponding y values by plugging in the x values in the function. So,

When x = 2, $y=f(2)=-(2)^3 + 4(2) + 2=2$

When x = 3, $y=f(3)=-(3)^3 + 4(3) + 2=-13$

Hence,

Average Rate of Change = $\frac{-13-2}{3-2}=-15$

Part 2:

The instantaneous rate of change is got by differentiating the function and plugging the 2 points and finding the difference.

First, let's differentiate:

$f(x)=-x^3+4x+2\\f'(x)=-3x^2+4$

Now, find the derivative at 3,

$f'(x)=-3x^2+4\\f'(3)=-3(3)^2+4=-23$

finding derivative at 2,

$f'(x)=-3x^2+4\\f'(2)=-3(2)^2+4=-8$

The instantaneous rate of change at x = 2 is -8 & at x = 3 is -23

6 0

3 years ago

Find the volume of a cube whose surface area is 150 ft2?

Brrunno [24]

Given:

Surface area of cube = 150 ft²

To Find:

Volume of cube

Solution:

As here in Question we are given Surface area of cube is 150 sq. feet. So, firstly we have find the side of edge of cube. Let 'a' be the edge of the cube

We know that,

$\: \: \: \: \dashrightarrow \sf \: \: \: \: Surface \: area_{(Cube)} = 6a^2 \\ \\$

Substituting the required values,

$\: \: \: \: \dashrightarrow \sf \: \: \: \: 150 = 6a^2 \\ \\ \: \: \: \: \dashrightarrow \sf \: \: \: \: \frac{150}{6} = {a}^{2} \\ \\ \: \: \: \: \dashrightarrow \sf \: \: \: \: 25 = {a}^{2} \\ \\ \: \: \: \: \dashrightarrow \sf \: \: \: \: \sqrt{25} = a \\ \\ \: \: \: \: \dashrightarrow \sf \: \: \: \: { \underline{ \boxed{ \sf{ \pink{5 = a}}}} } \\ \\$

Edge of the cube is 5 feet

Now,

$\: \: \: \: \dashrightarrow \sf \: \: \: \: Volume = (edge)^3 \\ \\ \: \: \: \: \dashrightarrow \sf \: \: \: \: Volume = (5)^3 \\ \\ \: \: \: \:\dashrightarrow \sf \: \: \: \: {\underline{\boxed{\sf{\pink{Volume =125 \: {ft}^{3}}}}}} \\ \\$

Hence,

Volume of the cube is 125 cu. feet

7 0

2 years ago

Read 2 more answers

Need help ASAP find the value of x

Brrunno [24]

Answer:

32 degrees

Step-by-step explanation:

The interior angles of a triangle always add up to 180.

Subtract the sum of 106 and 42 from 180.

180-(106+42)

180-(148)

x is equal to 32 degrees.

8 0

3 years ago

Read 2 more answers

(40 POINTS)

34kurt

Answer:

1. y= 25400(1 + 0.11)^x

2. 2019

Step-by-step explanation:

1. y = a(1 + r)^x

(exponential growth formula :

a = initial value (the amount before measuring growth or decay)

r = growth or decay rate (usually represented as a percentage and expressed as a decimal)

x = number of time units that have passed)

y= 25400(1 + 0.11)^x

so in 1 year, in 1996, we would say

y=25400(1+0.11)^1

y=25400(1.11)

y=28194

2. I found the answer by plugging in numbers into x

with x = 24

y= 25400(1+0.11)^24

y= 310874

so in 24 years, the population will surpass 302438 which would be 1995+24= 2019

3 0

3 years ago

Lisa spends 1/4 of her earnings on rent and 1/5 of her earnings on food. Let m stand to

Zarrin [17]

Answer:

Step-by-step explanation:

Let her total earnings be m

Rent = 1/4m

Food = 1/5m

Amount left = m - 1/4m - 1/5m

Amount left = (20m - 5m - 4m)/20

Amount left = 11m/20

4 0

3 years ago