[填空题]
The bolts on the cylinder head of an engine4oj;irxw 6bs9f)x9-3ri vxp c require tighm0zicjz* 8 f-f;uie 5dtening to a torque of 38 c5j zm -iz*fdief08;u$m \cdot N$ 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