A cable that weighs 6 lb/ft is used to lift 500 lb of coal up a mine shaft 400 ft deep. Find the work done. Show how to approximate the required work by a Riemann sum. (Let x be the distance in feet below the top of the shaft. Enter xi* as xi.)

Answers

Answer 1
Answer:

The work done to lift the coal is 6.8*10^5 ft-lb

Data;

  • weight of cable = 6lb/ft
  • weight of coal = 500lb
  • length of mine shaft = 400ft

Let the distance (ft) below top of the shaft be represented by x

The weight of the coal  to be lifted from mine = 500lb

Work Done

The work done to lift the coal is

work = force * displacement\nw=fx\nforce f(x) = 500 + 6x\nw_i= f(x_i)=[500+6x_i]\delta x\n

Taking the summation limit

w =  \lim_(0 \to 400) \sum [500+6x_i]\delta x\n \delta w = f(x) \delta x\n

we can take the integration of both sides where x will the range from 0 to 400.

\int \delta w = \int f(x) dx\n\int\limits^(400)_0{(500+6x)} \, dx \nw=[500x+3x^2]_0^4^0^0\nw=500(400-0)+ 3(400^2-0^2)\nw= 680000\nw=6.8*10^5 ft-lb

From the calculations above, the work done is 6.8*10^5 ft-lb

Learn more on work done on a lift here;

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Answer 2
Answer:

Answer:

8.2 *10^5 ft lb

Step-by-step explanation:

Wcoal = 800*500  = 400000 = 4*10^5 ft lb

Wrope =\int\limits^(400)_0 {6(400-y)} \, dy

Using a right Riemann sum

The width of the entireregion to be estimated = 400 - 0 = 400

Considering 8 equal subdivisions, then the width of each rectangular division is 400/8 = 50

F(x) = 6(400-y)

\left[\begin{array}{cccccccccc}x&0&50&100&150&200&250&300&350 &400\nf(x)&2400&2100&1800&1500&1200&900&600&300&0\end{array}\right]

Wrope = 50(2100) + 50(1800) + 50(1500) + 50(1200) + 50(900) + 50(600)

+ 50(300) + 50(0) = 420000 = 4.2 * 10^5 ft lb

Note: Riemann sum is an approximation, so may not give a accurate value

work done =  Wcoal + Wrope= 4*10^5+ 4.2 * 10^5 = 8.2 *10^5 ft lb


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David has four bags of apples and two bagsof mangoes. The first four bags contain
6 apples each and the bags with mangoes
contain 3 mangoes each. If David and his
friends ate 2 apples from each bag and 2
mangoes from each bag, what is the total
number of fruits left over?

Answers

Answer:

Step-by-step explanation: the step by step explanation is 6*4=24 so 24 apples then 3*2=6 so 6 mangoes then if 8 apples are ate then 4 mangoes are ate then (24+6)-(8+4)=30-12 so the answer is 18.

18 fruits left over
6 bags in total
4 bags x 6 apples each = 24 fruits
2 bags with 3 mangoes each= 6 fruits
Total 30 fruits
Friends ate 2 fruits from each of the 6 bags
They ate 12 fruits

30-12 = 18

Suppose you are a chemist who is trying to synthesize a specific compound. You have been working with a new technique and you think that this process can turn 60% of the input compounds into the desired synthesized compound, and want to attempt the process enough times to get an estimate that is within .04 of the true proportion that is converted. How many times should you execute the process to get the desired precision

Answers

Answer:

The sample size 'n' = 576

576 times should you execute the process to get the desired precision

Step-by-step explanation:

Explanation :-

Step(i)

Given data the process can turn 60% of the input compounds into the desired synthesized compound.

Sample proportion ' p' = 60% = 0.60

Given data the estimate within 0.04 of the true proportion that is converted

The margin of error of the true population proportion

                      M.E = 0.04

Step(ii)

The margin of error of the true population proportion is determined by

                M.E = ( Z_(0.05) √(p(1-p)) )/(√(n) )

               0.04 = ( 1.96 √(0.60(1-0.60)) )/(√(n) )

              √(n)  = ( 1.96 √(0.60(1-0.60)) )/(0.04 )    

      on calculation, we get

             √(n) = 24

squaring on both sides ,we get

             n = 576

Final answer:-

The sample size 'n' = 576

576 times should you execute the process to get the desired precision

Can someone please help me :)

Answers

Answer:

90 degree

Step-by-step explanation:

Three points A, B, and C are added and shown in attached picture.

As the property of inscribed angle in circle:

angle BAC = (1/2) x 88 = 44 deg

As the property of complement angle:

angle ABC = 180 - 89 = 91 deg

As the property of sum of three angles in a triangle:

angle ACB + angle ABC + angle BAC = 180 deg

=> angle ACB = 180 - angle ABC - angle BAC = 180 - 44 - 91 = 45 deg

One more time, we use the property of inscribed angle in circle:

x = 2 x angle ACB = 2 x 45 = 90 deg

Hope this helps!

Determine the wavelengths of all the possible photons that can be emitted from the n = 5 state of a hydrogen atom.

Answers

Answer:

Wavelengths of all possible photons are;

λ1 = 9.492 × 10^(-8) m

λ2 = 1.28 × 10^(-6) m

λ3 = 1.28 × 10^(-6) m

λ4 = 4.04 × 10^(-6) m

Step-by-step explanation:

We can calculate the wavelength of all the possible photons emitted by the electron during this transition using Rydeberg's equation.

It's given by;

1/λ = R(1/(n_f)² - 1/(n_i)²)

Where;

λ is wavelength

R is Rydberg's constant = 1.0974 × 10^(7) /m

n_f is the final energy level = 1,2,3,4

n_i is the initial energy level = 5

At n_f = 1,.we have;

1/λ = (1.0974 × 10^(7))(1/(1)² - 1/(5)²)

1/λ = 10535040

λ = 1/10535040

λ = 9.492 × 10^(-8) m

At n_f = 2,.we have;

1/λ = (1.0974 × 10^(7))(1/(2)² - 1/(5)²)

1/λ = (1.0974 × 10^(7))(0.21)

1/λ = 2304540

λ = 1/2304540

λ = 4.34 × 10^(-7) m

At n_f = 3, we have;

1/λ = (1.0974 × 10^(7))(1/(3)² - 1/(5)²)

1/λ = (1.0974 × 10^(7))(0.07111)

1/λ = 780373.3333333334

λ = 1/780373.3333333334

λ = 1.28 × 10^(-6) m

At n_f = 4, we have;

1/λ = (1.0974 × 10^(7))(1/(4)² - 1/(5)²)

1/λ = (1.0974 × 10^(7))(0.0225)

1/λ = 246915

λ = 1/246915

λ = 4.04 × 10^(-6) m

On a coordinate plane, an absolute value graph has a vertex at (1, negative 2.5). The graph shows the function f(x) = |x – h| + k. What is the value of k? k = –2.5 k = –1 k = 1 k = 2.5

Answers

9514 1404 393

Answer:

  (a)  k = –2.5

Step-by-step explanation:

When the function f(x) is transformed to f(x -h) +k, the graph is translated h units right and k units up.

If the absolute value function has its original vertex of (0, 0) moved to (1, -2.5), then (h, k) = (1, -2.5).

The value of k is -2.5.

_____

Additional comment

The above answer applies to the given problem statement. The question asked in the comment has a vertex of (0, 2.5), so (h, k) = (0, 2.5) for that question.

If you're going to copy the answer, make sure it is the answer to the question you're looking at.

In an absolute value function expressed as f(x) = |x – h| + k, the value of k corresponds to the y-coordinate of the function's vertex. In this case, as the vertex is at the point (1, -2.5), the value of k is -2.5.

The student's question relates to the concepts of Two-Dimensional (x-y). Graphing and the graphing of the absolute value function. It is vital to remember that the vertex of an absolute value graph in the form f(x) = |x – h| + k corresponds to the point (h, k) on the Cartesian coordinate plane. The student states that the vertex is at the point (1, -2.5), so based on our function analysis, the value of k, which represents the y-coordinate of the vertex, is -2.5. Therefore, the correct answer is k = -2.5.

For more about Absolute Value Graph here:

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Determine whether the following examples are discrete or continuous data sets. (a) The length of time it takes to fill up your gas tank. (b) The number of students applying to graduate schools. (c) The number of voters who vote Democratic. (d) The number of customers waiting in line at the grocery store

Answers

(a) The length of time it takes to fill up your gas tank - Continuous

(b) The number of students applying to graduate schools - Continuous

(c) The number of voters who vote Democratic - Discrete

(d) The number of customers waiting at the grocery store-Discrete

What is the difference between continuous and discrete data?

Continuous data can have an infinite range of values while Discrete data can take some certain values only.

Let us consider the given examples

a) The length of time it takes to fill up your gas tank.

In this case, the time duration can be of a wide range. Time taken while filling up a gas tank can take many values. So it is an example of continuous data.

b) The number of students applying to graduate schools.

In this case, the number of students applying to graduate schools can be of a wide range. it can be n number of values. So it is an example of continuous data.

c)The number of voters who vote Democratic.

The number of voters who vote can be of a certain value. Hence, this is an example of discrete data.

d)The number of customers waiting in line at the grocery store.

The number of customers waiting in line at the grocery store can be of a certain value. Hence, this is an example of discrete data.

Therefore, we can say that

(a) The length of time it takes to fill up your gas tank - Continuous

(b) The number of students applying to graduate schools - Continuous

(c) The number of voters who vote Democratic - Discrete

(d) The number of customers waiting at the grocery store-Discrete

To get more about continuous and discrete data refer to the link,

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Answer:

(a) The length of time it takes to fill up your gas tank - CONTINUOUS

(b) The number of students applying to graduate schools - CONTINUOUS

(c) The number of voters who vote Democratic - DISCRETE

(d) The number of customers waiting in line at the grocery store - DISCRETE

Step-by-step explanation:

To determine either the set of data are discrete or continuous, let consider their characteristics.

CONTINUOUS

continuous data is quantitative data, It can be measured, it has an infinite values within selected range.

DISCRETE

Discrete data is counted, it can only take certain values.