(3) For the tension force T = 675 lb applied at C on the frame, determine (a) the angle between the force and the +y-axis, and (b) the projection of the force onto line AB. Ans: (a) 81.5° (b) 633 lb 9' 12' * B 6' A 12' 12' 15' T = 675 lb -y

A 50 N force is applied at the end of a 20 cm wrench and makes an angle of 30° with the handle of the wrench. Find the magnitude of the torque. b. What is the maximum torque that can be exerted by a 50 N force on the wrench and а. how it can be achieved?

(4) Determine (a) the force component perpendicular to line OA and (b) then calculate the moment produced by the 4 lb force about point O. Ans: (a) 3.06 lb (b) Mo=24.5 lb-in CCW F=4 lb 10° 30°

(3) The power line is strung between A and B which are on the same horizontal plane. The tension force makes a 15° angle with the horizontal plane at A due to the sag of the cable. If the cable tension at A is T = 200 lb, express the tension as a vector. Ans: T=191.0+28.7-51.8 lb 18' 0 4.5' A 15° F 30' B

(5) The 16 N force is applied to the foot valve AC at point A as shown with a = 28°. Determine (a) the force component perpendicular to line BA and (b) then calculate the moment produced by the force about point B. Ans: (a) 7.51 N (b) MB = 1.277 N·m CCW 20° 16 N 170 mm 80 mm

Two construction workers are lifting a beam using ropes. Worker A pulls with a force of 500 newtons at an angle of 40°with the positive x-axis. Worker B is on the opposite side pulling with a force of 380 newtons at an angle of 115 ° with the positive x- axis. Find the (a) magnitude and (b) direction angle of the resultant force. (Round to the nearest hundredths)

(6) A force F is applied on bar BC at B through rod AB as shown. If the t-component of the force is F₁ = 50 lb, determine the n-, x-, and y-components of the force F. The t- axis is directed along bar BC, and the n-axis is perpendicular to the bar BC. Ans: Fn = 284 lb, Fx = -271 lb, Fy = -98.5 lb -30°4 F A 20°

(7) The force F is applied on the ball of the trailer hitch as shown. Determine the moment of the force about point O. Ans: Mo 102.8 lb-ft CCW 1.25" 130° F= 120 lb 11" 1.5"

(5) A force T is applied at the tip of the rod as shown. If the n- component of the force is T, = 35 lb, determine the t-, x-, and y-components of the force T. The t-axis is directed along the rod, and the n-axis is perpendicular to the rod. Ans: T₁ =-130.6 lb, Tx=-103.6 lb, Ty = -86.9 lb T n 40° O 55°

3m A. Find the unit vector that makes an angle (0 = - with the positive x-axis.