[填空题]
The bolts on the cylinder head of an engine require tightening to a eh .uoa-c2f4 mtorque 7en)zikxcrk 1e,8 .hqof 38rxknz,.8hqei kc7)e1 $m \cdot N$ 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