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Question 4 A composite spring consists of a steel close-coiled helical spring and a bronze close-coiled helical spring arranged in series. Data for the springs are given in the table below: Steel Spring Bronze Spring D D 40 mm 40 mm d 4.5 mm 4.5 mm n 10 ? G 80 GPa 40 GPa TAllowable 250 MPa 181 MPa 1 Determine the ratio between the number of coils in each spring if the deflection of the two springs is to be the same. /2/ 12/ 4.2 Calculate the number of coils of the bronze spring 4.3 Calculate the maximum load that can be carried by the composite spring. /5/ 4.4 Determine the total extension of the composite spring when subjected to the maximum load. /3/ 4.5 Calculate the total strain energy in the spring assembly. /3/ [15] Question 5