[填空题]
The bolts on the cylinder head of an engine requirr qlu s7h;*mzu0t cu2-e tightening to a torque of ez ml5s r4e8v+388e+v4rz seml5 $m \cdot N$ 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