Lab Problem Solving using MATLAB

ENGR1121 – Computing Applications in Mechanical Engineering Lab Problem Solving using MATLAB Lab due: end of lab Total points: 20 Labs are to be individual work. You may use MATLAB Marina, MATLAB’s help, and your notes. Lab work will be graded during lab time and working results must be shown to the lab instructor by the end of the scheduled lab time. All MATLAB programs and functions must be completed and submitted in accordance with the Computing Assignment Format and the MATLAB Coding Style. Submit an electronic copy of your lab work to the appropriate Dropbox Folder in GSU’s Folio by the end of lab. No hard copy needed unless specifically requested by the instructor. Grading Each problem will be graded according to: program design (identifying inputs/givens, process, and outputs; algorithm) and program style (program comments, variable names, proper formatted input and output including units) 25%, and program correctness 75%. Lab Work 1. (10 points) Captain Jack Sparrow has a problem at hand – his ship is sinking! He has to make a decision based on the following: he has several bags on deck with known weights (w) and monetary values of contents (v). If a bag weighs more than 50 lbs and has a value less than $100, then it must be thrown overboard. Write a MATLAB program that will a. Ask the user for each bag’s weight and value one at a time (using a for loop with the input command). Assume a value for the total number of bags (Nbags). b. Calculate the total weight of the bags on board the ship. Use a running sum inside the same for loop. c. Calculate the total value $$ of the bags on board the ship. Use a running sum inside the same for loop. d. Determine if the bags need to be thrown and which need not be thrown (decision d with 1 or 0). Use an if statement within the same for loop. e. Calculate the total weight of the bags on the ship after the above decision has been implemented. Use a running sum in the same if statement. f. Calculate the total value $$ of the bags on the ship after the above decision has been implemented. Use a running sum in the same if statement. g. Calculate the Captain’s loss in $$. h. Display as outputs all of the following: i. the total weight of the bags on board the ship ii. the total value $$ of the bags on board the ship iii. the total weight of the bags on the ship after the above decision has been implemented iv. the total value $$ of the bags on the ship after the above decision has been implemented v. the Captain’s loss in $$. 1 Instructor: Dr. Priya Goeser ENGR1121 – Computing Applications in Mechanical Engineering 2. Write a MATLAB program that will display a menu with the donut choices: glazed, cake, jelly, and crème; and display the cost of the donut selected from the menu. The donut costs are: glazed $0.50, cake $0.50, jelly $0.65, and crème $0.80. The menu can be generated using the MATLAB statement choice=menu('Donut Choices','glazed','cake','jelly','creme'); the menu function will return an integer corresponding to the number of the button selected. The variable choice will be assigned the value corresponding to the menu button pressed. This program (from the conditional structures lab) is only for buying 1 donut. (5 points) Include in the above code the calculation of the total cost, given the number of donuts purchased. If a dozen are purchased, a 5% discount is applied to the total cost. • Assume the user buys Ndonuts. • Use a for loop with a running sum to calculate the total cost • Use an if statement after the above loop to check and apply the discount • Assume that the discount is only for 12 donuts (not for multiple dozens) • Clearly display the total cost g x 2 + y0 , 2 2v cos θ where y is the height, x is the horizontal distance, θ is the initial angle, g is the acceleration due to gravity, v0 is the initial velocity and y0 is the initial height. Write a MATLAB program to find the trajectory for y0=0, v0=28 m/s, g=9.81 m/s2, θ =150. Use a range of horizontal distance from x = 0 to 80 m in increments of 5 m. Create a single plot of the height y (y-axis) vs. horizontal distance x (x-axis) for this initial angle θ. 3. The trajectory of an object can be modeled as: y = x tan θ − 2 0 Properly annotate the plot with grid lines, labels and maximize the use of the space by setting the y axis limits to 0 to 50 m. The x axis limits should be set to 0 to 80 m. (5 points) Write a MATLAB program which is a modification of the above program to find the set of trajectories if the initial angles θ range from 150 to 750 in increments of 150. All other parameters remain the same. • • • • Define theta as a vector using the given range values. Use a for loop that iterates over the indices of the vector theta or one that iterates over theta to calculate and plot the results for each theta. Create multiple plots on the same figure window (canvas) of the heights y (y-axis) vs. horizontal distance x (x-axis) for each of the initial angles. Use the MATLAB command hold on within the for loop. Properly annotate the plot with grid lines, labels and maximize the use of the space by setting the y axis limits to 0 to 50 m. The x axis limits may be left as 0 to 80 m. This is best done outside the for loop. 2 Instructor: Dr. Priya Goeser