[填空题]
The bolts on the cylkl-8 k- 5rcek(: pfjzsam *amtno*9y5inder n/mrm+lnjo+7d**rve head of an engine require tightening to a torque of 38 +/ me7 v+m djorn*lrn*$m \cdot N$ 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