A four-cylinder in-line engine has a reciprocating weight of 3 lb, a stroke of 6 in., and a connecting-rod length of 10 in. in each cylinder. The cranks are separated by 4 in. axially and 90° radially, as shown in Fig. 9.46. Find the unbalanced primary and secondary forces and moments with respect to the reference plane shown in Fig. 9.46 at an engine speed of 1500 rpm.
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