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125-04b-ex-1-eyq0z34k-0p345huy.pdf 125-04a-ys-gtdkvuhd.dwg 125-04b1-xeelmnp2.pdf MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 1 Name: _______________________________________ Team ___________________ Item ATV Lift Lift table Score Corrections 1 Top Pad Table /10 2 Idler Lift Arm Idler Frame / 3 Active Lift Arm Active Frame /20 4 Base Assembly Base Assembly /20 Individual Score: (1-6) 5 Cylinder Link Pair - / 6 Bicycle Stopping Reactions /40 7 Free Body Diagram Pipe (Length) /20 Team Score: (7-9) 8 Maximum Deflection /40 9 Maximum Stress /40 Total Score Total Percent % Multiplied by 10.00% % On Time: 0.20% % Added to Grade % Hand in ONE cover sheet each with Reaction Calculations Only one Pipe Support is necessary on one person’s cover sheet Individual scores apply to the ATV Lift/Lift Table & Bicycle Stopping calculations; everyone gets the same score for the Pipe Support calculations MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 2 MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 3 ATV Lift: (if that is the project that you chose) Use your Free Body Diagrams from last week. Find the reactions at the Top Pad. Use the regular analytical (fingers & a calculator) MA = 0, etc. Be sure to perform a check. Transfer the “actions” to the reactions on the Idler Lift Arm and the Active Lift Arm. Show the forces on the Idler Lift Arm. There isn’t any calculation here as it is a Link, this is simply for completeness. Show it in its actual orientation. Calculate the forces on the Active Lift Arm. First transfer the “action” from the Top Pad. The magnitude of the force due to the piston is as yet unknown, but its direction is known. The direction of this force is the angle of the Cylinder Link Pair as defined in the Layout Drawing. MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 4 Finally, find the reactions at the wheels on the Base Assembly. (The reactions at the wheels are vertical.) The force at Pin C is transferred from the Idler Lift Arm. The force at the other Pin D is transferred from the Active Arm just solved. The load from the Piston is actually at a fixed support and should be a force and a moment. This can be sidestepped (see right): draw a line through pins C & D and run the line of action of the Cylinder Link Pair through this line. Draw rectangles around the forces to find the vertical components. Complete the calculation with MG = 0, etc. Be sure to perform an independent check at the end. What should the reactions at the wheels add up to? Every force and moment combination can be replaced by a force alone in a certain position and line of action. MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 5 Lift Table: (if that is the project that you chose) Calculate the two reactions from the Frames to the 500lb load on the Table. Transfer the force from the pin at the front of the Table to the Idler Frame o Calculate the remaining two forces on the Idler Frame. Transfer the forces from the roller beneath the Table and the force at the center of the Idler Frame to the Active Frame and solve for the force in the Piston and the reaction at the pin where the Frame attaches to the Base. Remember that you know the direction of the force at the piston from your layout drawing. Use this angle to four (4) sig. fig. Finally, solve for the reactions at the wheels by transferring forces to the Base Assembly. What should the reactions at the wheels total to? Be sure to perform and independent check at the end. MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 6 Bicycle Stopping Reactions: (Individual) See attached Bicycle drawings. The center of gravity and weight is shown for the rider and the bicycle itself, as well as relevant dimensions. Assuming the bicycles are moving at a constant velocity in a straight line, find the reactions at the front and rear wheels. Assume that the rider weighs 160lb in each case: o The “ordinary” weighs 40lb o The “safety” weighs 21lb o The “recumbent” weighs 36lb Use SM = 0; take moments about where the front wheel touches the roadway and then about where the rear wheel touches the roadway. Then use SFy to check your answers. OVERWRITE THE ATTACHED AUTOCAD TO MAKE YOUR FBD FOR EACH CASE. Note that the first one already is an FBD If each bike is travelling at 18mph and needs to stop in 40ft, find the deceleration. Use equations from the previous assignment. Yes, the value is the same in each case, so only calculate once! Once something is being accelerated/decelerated, there is a force involved: F = ma, where m = W/g and g = 32.2 ft/s² (acceleration due to gravity) and ‘a’ is acceleration calculated above. E.g. If a = 10ft/sec² (it doesn’t!) for the rider: FR = (160/32.2)(10) = 49.69lb and for the bike: FB = (40/32.2)(10) = 12.42lb Then: Σ?? = −?(39.75) + 160(10.00) + 40(11.50) − 49.69(60.50) − 12.42(31.00) = 0 ∴ ? = +160(10.00) + 40(11.50) − 49.69(60.50) − 12.42(31.00) 39.75 = −33.49?? Σ?? = ?(39.75) − 160(29.75) − 40(28.25) − 49.69(60.50) − 12.42(31.00) = 0 ∴ ? = +160(29.75) + 40(28.25) + 49.69(60.50) + 12.42(31.00) 39.75 = 233.49?? . . . and check: Σ?? = −33.49 − 40 − 160 + 233.49 = 0 What does it mean when a reaction is negative? (R = -33.49lb) Be sure to find reactions when NOT braking first and then reactions when braking. MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 7 Now solve for reactions at the wheels for the “Safety” and the “Recumbent” using the deceleration that you calculated for the 40’ stopping distance. State if anyone is going over the handlebars. MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 8 MCDESG-125 Design Problems Assignment 4B Statics – Find Reactions MCDESG-125 Page 9 Pipe Support: (Group – attach one submission to one cover sheet) Draw a Free Body Diagram of the pipe between two supports. What kind of loading is this? Are the supports “simple”? Go to Appendix A-25 in “Applied Strength of Materials” by Mott or Appendix A14-3 in “Machine Elements in Mechanical Design” by Mott and look for an appropriate FBD. The load on the pipe is its own weight - is that a point load or distributed? Go to the Appendix where you found the FBD. Use the deflection formula to confirm that the pipe does not droop more than 1.00". Note that you need “E”, Young’s Modulus and “I”, the cross-sectional Moment of Inertia. Use E = 30 x 106 psi; look up (or calculate) I in a table of Pipe Properties. Note that you will have to calculate the deflection for 18" Sch 80 and 6" Sch 40. The lighter pipe may be more flexible. Calculate the stress and confirm that it is less than 10,000psi. Note that the formulas given are only for M, Moment. Use either: ? = ?? ? ?? ? = ? ? Design a python program that simulates the game rock, paper, and scissors. You are to keep track of your wins, losses, and ties. You are to allow the users to play over and over again until he or she decides to quit. After each throw, you will display the results of the throw followed by the current win, loss, tie numbers. A throw consists of the player picking either Rock, Paper, or Scissors followed by the computer randomly choosing Rock, Paper, or Scissors. Rules of the game: Rock beats Scissors. Paper beats Rock. Scissor beats paper. MENU: 1. Throw Rock 2. Throw Paper 3. Throw Scissors 4. Quit Sample Run: Option 1: == RESULTS == Computer Throws Scissors, you win Wins…………………...:1 Losses………………...: 0 Ties…………………..: 0 Longest Win Streak....: 1 Longest Lose Streak..: 0 Note: After each Throw you will display the results from above