[填空题]
The bolts on the cylinder head of an engine require tightening toyljln6ct5 ea68v fs 26 a torque of 3 z52y me 1,cegp3ck7fw8 57mz kc1 pe2,cgf3yew$m \cdot N$ 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