Problem 828 The bolts on the cylinder head of an engine requ

Problem 8.28 The bolts on the cylinder head of an engine require tightening to a torque of 69 mN .(Figure 1) Part A If a wrench is 28 cm long, what force perpendicular to the wrench must the mechanic exert at its end? Express your answer to two significant figures and include the appropriate units.
Part B 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. Express your answer to two significant figures and include the appropriate units

Solution

a)

Force required to produce th torque is

F=T/R =69/0.28

F=246.43 N

b)

R=15/2 =7.5 mm

The net torque still must be 69 mN. This must be produced by 6 forces, one at each of the 6 points.  

F=T/6R =69/6*7.5*10^-3

F=1533.33 N