[填空题]
The bolts on the cylij)qc7wx3-: u ep7dc;i/e mve4 9bqihondey)ssu+8h7qcq h:7/j z6ecqnmr head of an engine require tightening to a torque of 38 c )7 :hq6mcy/s suqqn h7ejz+8$m \cdot N$ If a wrench is 28 cm long, what force perpendicular to the wrench must the mechanic exert at its end? N If the six-sided bolt head is 15 mm in diameter, estimate the force applied near each of the six points by a socket wrench (Fig. 8–41). N