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question:An aerospace engineering student is designing a new type of aircraft wing that aims to revolutionize the aviation industry by significantly reducing drag while maximizing lift. The wing's cross-section is modeled as an airfoil described by a parametric function in terms of the variable ( t ):[ x(t) = a left(1 - e^{-bt} cos(ct) right) ][ y(t) = a left( e^{-bt} sin(ct) right) ]where ( t ) ranges from 0 to ( pi ), and ( a, b, c ) are positive real constants related to the wing's shape and material properties. 1. Determine the lift coefficient integral: Calculate the integral that represents the lift coefficient ( C_L ) of the wing, given by the following surface integral over the airfoil's surface ( S ): [ C_L = int_S rho left( frac{partial y}{partial t} frac{partial x}{partial t} right) dt ] where ( rho ) is the air density, assumed to be constant.2. Optimize the wing's shape: Find the values of ( a, b, c ) that maximize the lift-to-drag ratio ( frac{C_L}{C_D} ), where the drag coefficient ( C_D ) is given by: [ C_D = int_0^pi left( frac{partial^2 x}{partial t^2} + frac{partial^2 y}{partial t^2} right)^2 dt ] Provide the necessary conditions for ( a, b, ) and ( c ) to achieve this optimization.
answer:Let's tackle the problem step-by-step. Step 1: Calculate the Lift Coefficient ( C_L )Given:[ x(t) = a left(1 - e^{-bt} cos(ct) right) ][ y(t) = a left( e^{-bt} sin(ct) right) ]We need to find:[ C_L = int_S rho left( frac{partial y}{partial t} frac{partial x}{partial t} right) dt ]First, compute the partial derivatives:[ frac{partial x}{partial t} = a left( b e^{-bt} cos(ct) + c e^{-bt} sin(ct) right) ][ frac{partial y}{partial t} = a left( -b e^{-bt} sin(ct) + c e^{-bt} cos(ct) right) ]Next, multiply the partial derivatives:[ frac{partial y}{partial t} frac{partial x}{partial t} = a^2 left( -b e^{-bt} sin(ct) + c e^{-bt} cos(ct) right) left( b e^{-bt} cos(ct) + c e^{-bt} sin(ct) right) ]Simplify the expression:[ frac{partial y}{partial t} frac{partial x}{partial t} = a^2 e^{-2bt} left( -b sin(ct) cos(ct) + c cos^2(ct) + b sin^2(ct) right) ][ = a^2 e^{-2bt} left( -b sin(ct) cos(ct) + c cos^2(ct) + b sin^2(ct) right) ]We can rewrite the integrand in a more tractable form:[ -b sin(ct) cos(ct) + b sin^2(ct) = b sin(ct) left( sin(ct) - cos(ct) right) ]Thus:[ frac{partial y}{partial t} frac{partial x}{partial t} = a^2 e^{-2bt} left( b sin(ct) left( sin(ct) - cos(ct) right) + c cos^2(ct) right) ]The integral for ( C_L ) is:[ C_L = rho int_0^pi a^2 e^{-2bt} left( b sin(ct) left( sin(ct) - cos(ct) right) + c cos^2(ct) right) dt ] Step 2: Optimize the Wing's ShapeGiven:[ C_D = int_0^pi left( frac{partial^2 x}{partial t^2} + frac{partial^2 y}{partial t^2} right)^2 dt ]We need to find the second derivatives:[ frac{partial^2 x}{partial t^2} = a left( -b^2 e^{-bt} cos(ct) - 2bc e^{-bt} sin(ct) - c^2 e^{-bt} cos(ct) right) ][ = a e^{-bt} left( -b^2 cos(ct) - 2bc sin(ct) - c^2 cos(ct) right) ][ = a e^{-bt} left( -(b^2 + c^2) cos(ct) - 2bc sin(ct) right) ][ frac{partial^2 y}{partial t^2} = a left( b^2 e^{-bt} sin(ct) - 2bc e^{-bt} cos(ct) - c^2 e^{-bt} sin(ct) right) ][ = a e^{-bt} left( (b^2 - c^2) sin(ct) - 2bc cos(ct) right) ]Then:[ frac{partial^2 x}{partial t^2} + frac{partial^2 y}{partial t^2} = a e^{-bt} left( -(b^2 + c^2) cos(ct) - 2bc sin(ct) + (b^2 - c^2) sin(ct) - 2bc cos(ct) right) ][ = a e^{-bt} left( -(b^2 + c^2 + 2bc) cos(ct) + (b^2 - c^2 - 2bc) sin(ct) right) ]Finally:[ C_D = int_0^pi left( a e^{-bt} left( -(b^2 + c^2 + 2bc) cos(ct) + (b^2 - c^2 - 2bc) sin(ct) right) right)^2 dt ] Final Answer:To maximize the lift-to-drag ratio ( frac{C_L}{C_D} ), you would need to balance the constants ( a, b, c ) such that both the lift integral ( C_L ) and the resulting drag ( C_D ) are optimized. This typically involves setting up and solving a system of equations derived from the calculus of variations, which might be complex and require numeric methods or optimization algorithms.Final Answer: The problem requires solving complex integrals and derivatives, typically optimized using numeric methods. The values of ( a, b, c ) that maximize ( frac{C_L}{C_D} ) need to be found through detailed computation or optimization techniques.
question:As a conservative Christian American parent who believes in biological determinism, you are interested in understanding how genetic inheritance can influence the height of your children. Assume that height is determined by a combination of genetic factors and environmental factors, and that genetic factors follow a normal distribution.1. Given that the height of the father follows a normal distribution with a mean of 70 inches and a standard deviation of 2 inches, and the height of the mother follows a normal distribution with a mean of 65 inches and a standard deviation of 1.5 inches, determine the expected mean and variance of the heights of their children, considering that the genetic contribution to height is 70% from the father and 30% from the mother.2. If environmental factors contribute an additional independent normal distribution with a mean of 0 inches and a standard deviation of 1 inch to the height of the children, calculate the overall expected mean and variance of the heights of the children.
answer:To solve this problem, we need to combine the genetic contributions from both parents and the environmental factors to determine the expected mean and variance of the heights of their children.Step 1: Calculate the genetic contribution from both parents.Given:- The father's height follows a normal distribution with mean ( mu_f = 70 ) inches and standard deviation ( sigma_f = 2 ) inches.- The mother's height follows a normal distribution with mean ( mu_m = 65 ) inches and standard deviation ( sigma_m = 1.5 ) inches.The genetic contribution to the child's height is 70% from the father and 30% from the mother.Step 2: Calculate the expected mean height of the children from genetic factors.The expected mean height ( mu_c ) from genetic factors is given by:[mu_c = 0.7 times mu_f + 0.3 times mu_m]Substitute the values:[mu_c = 0.7 times 70 + 0.3 times 65 = 49 + 19.5 = 68.5 text{ inches}]Step 3: Calculate the variance of the genetic contribution.The variance of the child's height from genetic factors ( sigma_c^2 ) is given by:[sigma_c^2 = (0.7 times sigma_f)^2 + (0.3 times sigma_m)^2]Substitute the values:[sigma_c^2 = (0.7 times 2)^2 + (0.3 times 1.5)^2 = (1.4)^2 + (0.45)^2 = 1.96 + 0.2025 = 2.1625]Step 4: Incorporate the environmental factors.Environmental factors contribute an additional independent normal distribution with mean ( mu_e = 0 ) inches and standard deviation ( sigma_e = 1 ) inch.Step 5: Calculate the overall variance of the heights of the children.Since the environmental factors are independent, the overall variance ( sigma_{total}^2 ) is the sum of the variances from genetic factors and environmental factors:[sigma_{total}^2 = sigma_c^2 + sigma_e^2]Substitute the values:[sigma_{total}^2 = 2.1625 + 1^2 = 2.1625 + 1 = 3.1625]Step 6: Summarize the overall expected mean and variance.The overall expected mean height of the children is ( mu_c = 68.5 ) inches, and the overall variance is ( sigma_{total}^2 = 3.1625 ).Final Answer: The final answer is the overall expected mean height of the children is 68.5 inches, and the overall variance is 3.1625. I hope it is correct.
question:A competitive dog show participant, Clara, has a Yorkshire Terrier named Bella. Clara is preparing Bella for the upcoming show, where performance in various categories will be judged. The final score is determined by a weighted average of Bella's scores in three categories: agility, obedience, and appearance.1. Clara estimates Bella's scores in the categories as follows: - Agility: 85 ± 5 - Obedience: 90 ± 4 - Appearance: 92 ± 3 The weights for each category are: - Agility: 30% - Obedience: 40% - Appearance: 30% Calculate the range of possible final scores Bella could achieve in the show, considering the given uncertainties in each category.2. To improve her chances, Clara decides to invest additional training time, which is represented by a function T(x) = 20 * ln(x + 1), where x is the number of hours spent training. This additional training increases Bella's score in each category by T(x) points. If Clara has a maximum of 100 hours available for additional training, determine the optimal allocation of training hours across the three categories to maximize Bella's final score. Formulate this as an optimization problem and set up the necessary equations to solve it.
answer:Let's solve the given math problem step-by-step. Part 1: Calculating the Range of Possible Final ScoresThe final score is a weighted average of Bella's scores in three categories. The weights and estimated scores (with uncertainties) are given as:- Agility: 85 ± 5 (weight: 30%)- Obedience: 90 ± 4 (weight: 40%)- Appearance: 92 ± 3 (weight: 30%)To find the range of possible final scores, we need to calculate the minimum and maximum scores for each category and then compute the weighted average.# Calculating the Minimum and Maximum Scores:1. Agility: - Minimum Score: (85 - 5 = 80) - Maximum Score: (85 + 5 = 90)2. Obedience: - Minimum Score: (90 - 4 = 86) - Maximum Score: (90 + 4 = 94)3. Appearance: - Minimum Score: (92 - 3 = 89) - Maximum Score: (92 + 3 = 95)# Calculating the Minimum and Maximum Final Scores:To find the minimum final score:[text{Minimum Final Score} = 0.30 times 80 + 0.40 times 86 + 0.30 times 89][= 24 + 34.4 + 26.7 = 85.1]To find the maximum final score:[text{Maximum Final Score} = 0.30 times 90 + 0.40 times 94 + 0.30 times 95][= 27 + 37.6 + 28.5 = 93.1] Part 2: Optimizing Training Time AllocationThe additional training function is given by ( T(x) = 20 times ln(x + 1) ), where ( x ) is the number of hours spent training in each category. Clara has a maximum of 100 hours available for additional training.We need to maximize Bella's final score by optimally allocating the training hours in each category. Let ( x_1 ), ( x_2 ), and ( x_3 ) represent the hours spent on training for agility, obedience, and appearance, respectively. Then:[x_1 + x_2 + x_3 = 100]The scores after training for each category are:- Agility: ( 85 + 20 ln(x_1 + 1) )- Obedience: ( 90 + 20 ln(x_2 + 1) )- Appearance: ( 92 + 20 ln(x_3 + 1) )The weighted final score ( S ) after training is:[S = 0.30 times (85 + 20 ln(x_1 + 1)) + 0.40 times (90 + 20 ln(x_2 + 1)) + 0.30 times (92 + 20 ln(x_3 + 1))]This can be simplified to:[S = 0.30 times 85 + 0.40 times 90 + 0.30 times 92 + 6 ln(x_1 + 1) + 8 ln(x_2 + 1) + 6 ln(x_3 + 1)]We need to maximize ( S ) subject to the constraint ( x_1 + x_2 + x_3 = 100 ).Using Lagrange multipliers, we set:[mathcal{L}(x_1, x_2, x_3, lambda) = 6 ln(x_1 + 1) + 8 ln(x_2 + 1) + 6 ln(x_3 + 1) + lambda (100 - x_1 - x_2 - x_3)]Taking the partial derivatives and setting them to zero:[frac{partial mathcal{L}}{partial x_1} = frac{6}{x_1 + 1} - lambda = 0 implies lambda = frac{6}{x_1 + 1}][frac{partial mathcal{L}}{partial x_2} = frac{8}{x_2 + 1} - lambda = 0 implies lambda = frac{8}{x_2 + 1}][frac{partial mathcal{L}}{partial x_3} = frac{6}{x_3 + 1} - lambda = 0 implies lambda = frac{6}{x_3 + 1}][frac{partial mathcal{L}}{partial lambda} = 100 - x_1 - x_2 - x_3 = 0]From the above equations:[frac{6}{x_1 + 1} = frac{8}{x_2 + 1} = frac{6}{x_3 + 1}]Solving these, we get:[x_1 + 1 = frac{3}{4}(x_2 + 1)][x_3 + 1 = x_1 + 1]Let ( x_1 + 1 = a ), ( x_2 + 1 = b ), and ( x_3 + 1 = c ):[a = frac{3}{4}b][c = a]Thus:[x_1 = a - 1][x_2 = b - 1][x_3 = a - 1]Using the constraint ( x_1 + x_2 + x_3 = 100 ):[(a - 1) + (b - 1) + (a - 1) = 100][2a + b - 3 = 100]Substituting ( a = frac{3}{4}b ):[2 left(frac{3}{4}bright) + b - 3 = 100][frac{3}{2}b + b - 3 = 100][frac{5}{2}b = 103][b = frac{103 times 2}{5} = 41.2]Then:[a = frac{3}{4} times 41.2 = 30.9]Thus:[x_1 = 30.9 - 1 = 29.9][x_2 = 41.2 - 1 = 40.2][x_3 = 30.9 - 1 = 29.9]Final Answer: The final answer is as follows:- The range of possible final scores Bella could achieve is ([85.1, 93.1]).- The optimal allocation of training hours across the three categories to maximize Bella's final score is: - Agility: 29.9 hours - Obedience: 40.2 hours - Appearance: 29.9 hoursI hope it is correct.
question:Consider a researcher, Dr. Euler, who is a longtime colleague and collaborator from his days at the Max Planck Institute for Informatics. Dr. Euler is working on optimizing a large-scale distributed computing system and is currently focusing on minimizing communication overhead between nodes in a network. Assume the network can be represented as a weighted, undirected graph ( G = (V, E) ), where ( V ) is the set of nodes and ( E ) is the set of edges with weights ( w(e) ) representing the communication cost between nodes.1. Given a connected graph ( G ) with ( n ) nodes and ( m ) edges, devise an algorithm that finds the minimum spanning tree (MST) of ( G ). Provide a proof that your algorithm correctly finds the MST and analyze its time complexity.2. Suppose that after constructing the MST, Dr. Euler needs to ensure fault tolerance by adding the minimum number of edges to the MST such that the resultant subgraph remains connected even if any single edge in the original MST fails. Formulate and prove a method to determine which additional edges (and how many) need to be added to achieve this fault tolerance.
answer:Let's solve the given problem step-by-step. Part 1: Finding the Minimum Spanning Tree (MST)To find the MST of a connected graph ( G = (V, E) ) with ( n ) nodes and ( m ) edges, we can use Kruskal's algorithm or Prim's algorithm. Here, we will describe Kruskal's algorithm:Kruskal’s Algorithm:1. Sort all edges: Sort all the edges in the graph ( E ) in non-decreasing order of their weights ( w(e) ).2. Initialize disjoint sets: Create a disjoint-set data structure (Union-Find) to keep track of the components of the graph.3. Iterate through edges: Iterate through the sorted edges and for each edge ( e ): - Check if the nodes connected by ( e ) belong to different components using the Union-Find data structure. - If they belong to different components, add ( e ) to the MST and union the sets of the two nodes.4. Stop when MST is complete: Continue this process until the MST contains ( n-1 ) edges.Proof of Correctness:Kruskal's algorithm works because it follows the greedy strategy of always picking the smallest edge that does not form a cycle in the MST. By always picking the smallest weight edge, we ensure that the total weight of the MST is minimized. The use of the Union-Find data structure ensures that no cycles are formed, thereby maintaining the acyclic property of the MST.Time Complexity Analysis:- Sorting the edges: ( O(m log m) )- Union-Find operations: ( O(m alpha(n)) ), where ( alpha ) is the inverse Ackermann function, which is very slow-growing and can be considered nearly constant for practical purposes.- Total time complexity: ( O(m log m) ) Part 2: Ensuring Fault ToleranceAfter constructing the MST, we need to add the minimum number of edges to ensure that the subgraph remains connected even if any single edge in the original MST fails. This problem can be solved by finding a minimal set of edges that, when added to the MST, converts it into a 2-edge-connected graph.Method to achieve fault tolerance:1. Identify bridges: First, identify all the bridges in the MST. A bridge is an edge whose removal increases the number of connected components.2. Add additional edges: For each bridge, add an edge that connects the two components formed by the removal of the bridge. This edge must be chosen from the original graph ( G ) but not in the MST.Proof of Correctness:By adding an edge for each bridge, we ensure that even if any single edge (bridge) in the MST fails, there is an alternative path connecting the two components. This makes the graph 2-edge-connected, ensuring fault tolerance.Steps to determine additional edges:- Use Depth-First Search (DFS) to find all bridges in the MST. This can be done in ( O(n + m) ) time.- For each bridge, find an edge from the original graph that connects the two components formed by the bridge removal. This can be achieved by checking the remaining edges in ( O(m) ) time.Total time complexity: ( O(n + m) )Final Answer: The final answer is that the MST can be found using Kruskal's algorithm with a time complexity of ( O(m log m) ), and fault tolerance can be achieved by identifying bridges and adding necessary edges with a total time complexity of ( O(n + m) ). I hope it is correct.
question:An aspiring young athlete, Alex, is training to become as successful as Athing Mu and Sydney McLaughlin. Alex is focusing on both the 800 meters (inspired by Athing Mu) and the 400 meters hurdles (inspired by Sydney McLaughlin).1. Alex wants to optimize his training schedule. He can allocate a maximum of 20 hours per week for training. He decides to spend ( x ) hours per week training for the 800 meters and ( y ) hours per week training for the 400 meters hurdles. The effectiveness of his training for the 800 meters can be modeled by the function ( E_1(x, y) = 3x^2 + 2xy ), while the effectiveness for the 400 meters hurdles can be modeled by the function ( E_2(x, y) = 4y^2 + xy ). What values of ( x ) and ( y ) maximize the total training effectiveness ( E(x, y) = E_1(x, y) + E_2(x, y) ) subject to the constraint ( x + y leq 20 )?2. After optimizing his training schedule, Alex notices that his improvement rates for the 800 meters and the 400 meters hurdles are different. Suppose his running times in seconds for the 800 meters and the 400 meters hurdles are given by the functions ( T_1(x, y) = frac{800}{sqrt{E_1(x, y) + 1}} ) and ( T_2(x, y) = frac{400}{sqrt{E_2(x, y) + 1}} ), respectively. If Alex’s goal is to have his combined time for both events under 180 seconds, what are the conditions on ( x ) and ( y ) to meet this goal?
answer: Problem 1: Maximizing Training Effectiveness1. Objective Function: We need to maximize the total training effectiveness ( E(x, y) = E_1(x, y) + E_2(x, y) ) where: [ E_1(x, y) = 3x^2 + 2xy ] [ E_2(x, y) = 4y^2 + xy ] Thus, [ E(x, y) = (3x^2 + 2xy) + (4y^2 + xy) = 3x^2 + 2xy + 4y^2 + xy = 3x^2 + 3xy + 4y^2 ]2. Constraint: The constraint is ( x + y leq 20 ).To find the maximum of ( E(x, y) ) under the constraint ( x + y leq 20 ), we can use the method of Lagrange multipliers. The Lagrangian function ( mathcal{L}(x, y, lambda) ) is given by:[mathcal{L}(x, y, lambda) = 3x^2 + 3xy + 4y^2 + lambda (20 - x - y)]3. Partial Derivatives: We take the partial derivatives of ( mathcal{L} ) with respect to ( x ), ( y ), and ( lambda ), and set them to zero: [ frac{partial mathcal{L}}{partial x} = 6x + 3y - lambda = 0 quad text{(1)} ] [ frac{partial mathcal{L}}{partial y} = 3x + 8y - lambda = 0 quad text{(2)} ] [ frac{partial mathcal{L}}{partial lambda} = 20 - x - y = 0 quad text{(3)} ]4. Solving the System of Equations: From equation (3): [ x + y = 20 quad text{(4)} ] Subtract equation (1) from equation (2): [ (3x + 8y - lambda) - (6x + 3y - lambda) = 0 ] [ 3x + 8y - 6x - 3y = 0 ] [ -3x + 5y = 0 ] [ y = frac{3}{5}x quad text{(5)} ] Substitute equation (5) into equation (4): [ x + frac{3}{5}x = 20 ] [ frac{8}{5}x = 20 ] [ x = frac{5}{8} times 20 = 12.5 ] [ y = 20 - x = 20 - 12.5 = 7.5 ] Problem 2: Combined Time Constraint1. Running Times: The running times are given by: [ T_1(x, y) = frac{800}{sqrt{E_1(x, y) + 1}} ] [ T_2(x, y) = frac{400}{sqrt{E_2(x, y) + 1}} ] Using the values ( x = 12.5 ) and ( y = 7.5 ): [ E_1(12.5, 7.5) = 3(12.5)^2 + 2(12.5)(7.5) = 3(156.25) + 187.5 = 656.25 ] [ E_2(12.5, 7.5) = 4(7.5)^2 + (12.5)(7.5) = 4(56.25) + 93.75 = 318.75 ] [ T_1(12.5, 7.5) = frac{800}{sqrt{656.25 + 1}} = frac{800}{sqrt{657.25}} ] [ T_2(12.5, 7.5) = frac{400}{sqrt{318.75 + 1}} = frac{400}{sqrt{319.75}} ]2. Combined Time: Alex’s goal is to have his combined time under 180 seconds: [ T_1(12.5, 7.5) + T_2(12.5, 7.5) < 180 ] Approximating the values: [ sqrt{657.25} approx 25.63, quad T_1(12.5, 7.5) approx frac{800}{25.63} approx 31.2 ] [ sqrt{319.75} approx 17.88, quad T_2(12.5, 7.5) approx frac{400}{17.88} approx 22.4 ] [ T_1(12.5, 7.5) + T_2(12.5, 7.5) approx 31.2 + 22.4 = 53.6 ]Since this combined time is well under 180 seconds, the conditions on ( x ) and ( y ) to meet this goal are satisfied with the values found. Final AnswerThe final answer is ( x = 12.5 ) hours and ( y = 7.5 ) hours. I hope it is correct.
question:A professional pianist is preparing for a concert where they will play a piece of music by a composer they are not familiar with, Luciano Berio. To better understand the piece, they decide to analyze the structure mathematically. The piece is divided into multiple sections, each with its own time signature and rhythmic complexity.1. The pianist discovers that one section of Berio’s piece is structured in a way that it alternates between 7/8 and 5/8 time signatures. If the pianist wants to calculate the total duration of this section, assuming it consists of 28 measures of 7/8 and 20 measures of 5/8, and the tempo is set to 120 beats per minute (bpm), how many seconds will this section last?2. In another section, the pianist notes that a specific motif repeats every 3 measures. This motif contains a series of polyrhythms where two voices play in a 4:3 ratio. If each measure is in 4/4 time, and the motif starts at the beginning of the section and the section consists of 24 measures, how many times will the motif complete within this section?Use your advanced mathematical skills to solve these problems, keeping in mind the unique time signature challenges and rhythmic complexities inherent in unfamiliar contemporary music.
answer:Let's tackle the problem step-by-step. Part 1: Calculate the Total Duration of the SectionGiven:- 28 measures of 7/8 time signature- 20 measures of 5/8 time signature- Tempo = 120 beats per minute (bpm)First, let's calculate the total number of beats for each part of the section.1. Beats in 7/8 Measures: - Each measure of 7/8 has 7 beats. - Total beats = 28 measures * 7 beats/measure = 196 beats2. Beats in 5/8 Measures: - Each measure of 5/8 has 5 beats. - Total beats = 20 measures * 5 beats/measure = 100 beats3. Total Beats in the Section: - Total beats = 196 beats + 100 beats = 296 beatsNext, we need to calculate the duration in seconds. Given the tempo is 120 bpm:- 1 minute = 60 seconds- 120 beats are played in 60 secondsThus, 1 beat = 60 seconds / 120 beats = 0.5 seconds per beatTotal duration in seconds:- Total duration = 296 beats * 0.5 seconds/beat = 148 seconds Part 2: Calculate the Number of Times the Motif CompletesGiven:- The motif repeats every 3 measures- Each measure is in 4/4 time- The section consists of 24 measuresWe need to determine how many times the motif will complete within these 24 measures.1. Total Measures: - The section has 24 measures.2. Measures per Motif: - Each motif repeats every 3 measures.3. Number of Motif Repetitions: - Number of times the motif completes = Total measures / Measures per motif - Number of times the motif completes = 24 measures / 3 measures/motif = 8 times Final AnswerThe final answer is:1. The total duration of the section is 148 seconds.2. The motif completes 8 times within the 24 measures.I hope it is correct.