Chapter 4, Problem 120P

While cutting in a sport, an individual generates the following forces surrounding their ankle joint. The Achilles tendon is creating an eccentric force that is equal to 900 N directed down and to the right at an angle of 80 degrees below the right horizontal. They also have a GRF that is directed up and to the left at a magnitude of 3100 Newtons that is directed up and to the left at an angle of 82 degrees above the left horizontal. The lateral malleolus of the ankle joint helps to create a stable base for the ankle joint in the frontal (horizontal plane) and can produce up to a maximum horizontal reaction force of 200 N. After that it must rely on the ankle ligaments to help in stabilizing the joint. Part A) How much force, if any, do the ankle ligaments need to produce during this movement if the goal is to create a static horizontal situation? Part B) What is the resultant force and direction of this movement without the addition of the ankle ligaments, if the Force of gravity is…

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The forces acting on the arm of an athlete doing shoulder exercises are shown in the figure. The athlete holds his arm at an angle of β = 30° with the horizontal axis . Point O represents the axis of rotation in the shoulder joint, point A represents the connection point of the deltoid muscle to the humerus, point B represents the center of gravity of the arm, and point C represents the application point of the force acting on the hand. The distances between the rotation axis (O point) of the shoulder joint and the points A, B and C are a=22 cm , b =33 cm and c= 60 cm , respectively .  A force of F= 120 N,  which makes an angle of γ=30° with the vertical from the point C, acts on the athlete's hand  .   Weight of the athlete's armW= 80 N. The direction of application of the Fm muscle force makes an angle of α=20° with the longitudinal axis of the arm. According to this; a) Calculate the muscle strength  F M b) Calculate  the angle θ of the joint reaction force F J with the horizontal.…

Q5: The forces F1=6 kN, F2= 5 kN, and F3= 8 kN as shown in the Figure below, all of which act on point A of the bracket, are specified in three different ways. Determine the x and y scalar components of each of the three forces. F= 500 N F = 600 N 3 35 0m 0.2 m- 03 m F = 800 N B -0.4 m

- 1.5 kN-m =-0.9 F+0.6 F3D2.33 kN Example The device shown is a part of an automobile seat- back-release mechanism. The part is subjected to the 4-N force exerted at A and a 300-N-mm restor ing moment exerted by a hidden torsional spring Determine the y-intercept of the line of action of the single equivalent force. א 4_F 10 mm 15 40mm 300 N-mm

The weight of the limb is W=15 lbs.The contact of foot with the ground can be modeled as a pin/hinge here. Determine the reaction force of the ground and the reaction at the knee joint and its direction/angle θ. Note: use the thee force member condition to find the angle of FK.Q4.As it’s been shown in the below figure,a person is using an exercise machine. Points A and B correspond to the shoulder and elbow joints, respectively. Relative to the person, the upper arm (AB) is extended toward the left (x-direction) and the lower arm (BC) is extended forward (z-direction). At this instant, the person is holding a handle that is connected by a cable to a suspending weight. The weight applies an upward (in the y-direction) force with magnitude F on the arm at point C. The lengths of the upper arm and lower arm are AB̅̅̅̅= 20cm and BC̅̅̅̅= 25cm, respectively, and the magnitude of the applied force is F = 400 N.Determine the components of reaction developed at the shoulder joint A When the…

5. The figure below represents the anatomy of the lower limb when balanced on your toes and the body weight acts through the tibia. The Achilles Tendon makes an angle (0) of 8° with the vertical and for this foot x1 is 6.2 cm and x2 is 12.3 cm. Calf Muscle Tibia Achilles Tendon Calculate the tension (T) in the Achilles Tendon if a 70 kg man stands on the toes of both feet. Using the values in this example what is the mechanical advantage for this lever and describe what that means in terms of the efficiency of the lever.

Equilibrium of Concurrent Force System. The piston of a reciprocating engine exerts a force of 175 kN on the crosshead when the crank is 45° (angle B) past TDC. If the stroke of the piston is 800 mm and the length of the connecting rod is 1.80 m, find the guide force and the force in the connecting rod. Hint: 1=½ stroke; Angle o may be solved using Sine Law in AACO. K= Compressive Force in the connecting Rod E= Piston Effort 70 120 F, = Guide Force Fig. P-1 Fig. P-2 a Tools: EF cos0=0; F sin .=0. R = Ev)* + (E#): ; R 771 =- : tane = sin A sin B sin C