A machinist is using a wrench to loosen a nut. The wrench is 25.0 cm long, and he exerts a 17.0-N force at the end of the handle at 37° with the handle (?Fig. E10.7?). (a) What torque does the machinist exert about the center of the nut? (b) What is the maximum torque he could exert with this force, and how should the force be oriented?

Solution 8E Problem (a) Step 1: Length of the wrench l = 25.0 cm or 0.25 m Force exerted by the wrench F = 17.0 N Angle = 37° Torque exerted = Fl.sin Step 2: Substituting known quantities = 17*0.25*sin37° = 2.56 Nm Problem (b) Step 1: To find maximum torque to be attained with this force For maximum torque the force must be applied perpendicular to the wrench. That is = 90° We know that sin 90° =1,