Problem 7 The hook wrench or pin spanner is used to turn shafts and collars. If a moment of 80 N·m is re- quired to turn the 200-mm-diameter collar about its center O under the action of the applied force P, de- termine the contact force R on the smooth surface at A. Engagement of the pin at B may be considered to occur at the periphery of the collar. Ans. R=1047 N P B 120° 100 mm 0 A 375 mm