A worker leans over and picks up a 150 N box at a distance of 1.0 m from the axis of rotation in her spine. Neglecting the effect of body weight, how much-added force is required of the low back muscles with an average moment arm of 10 cm to stabilize the box in the position shown? Using static equilibrium calculations, how much added force is required of the low back muscles with the moment arm and position of box

A worker leans over and picks up a 150 N box at a distance of 1.0 m from the axis of rotation in her spine. Neglecting the effect of body weight, how much-added force is required of the low back muscles with an average moment arm of 10 cm to stabilize the box in the position shown? Using static equilibrium calculations, how much added force is required of the low back muscles with the moment arm and position of box

International Edition---engineering Mechanics: Statics, 4th Edition

4th Edition

ISBN:9781305501607

Author:Andrew Pytel And Jaan Kiusalaas

Publisher:Andrew Pytel And Jaan Kiusalaas

Chapter7: Dry Friction

Section: Chapter Questions

Problem 7.78P: The figure shows a steel bar being processed by a rolling mill. Given that P=80kN and r =0.016,...

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The figure shows a steel bar being processed by a rolling mill. Given that P=80kN and r =0.016, determine the force F required to advance the bar at a constant speed.
Find the stable equilibrium position of the system described in Prob. 10.56 if m = 2.06 kg.
The quadriceps tendon attaches to the tibia at a 30°angle 4 cm from the joint center at the knee. When an 80 N weight is attached to the ankle 28 cm from the knee joint, how much force is required of the quadriceps to maintain the leg in a horizontal position? What is the magnitude and direction of the reaction force exerted by the femur on the tibia? (Neglect the weight of the leg and the action of other muscles.)
The quadriceps tendon attaches to the tibia at a 30° angle 4 cm from the joint center at the knee. When an 80 N weight is attached to the ankle 28 cm from the knee joint, how much force is required of the quadriceps to maintain the leg in a horizontal position? When the subject mass is 75 kg, what is the magnitude and direction of the reaction force exerted by the femur on the tibia? (Utilize “Foot and leg” in the included chart to obtain weight of the lower leg and location of COM. Neglect the action of other muscles.)
The hanging mobile pictured above consists of two masses, m1 and m2, suspended from a uniform 10 cm long rod, which is in turn suspended from the ceiling at an angle of 70 as pictured above. The mass m1 is 0.02 kg, while the mass of the rod is mr = 0.01 kg. Assuming the mobile is in a state of static equilibrium, find the value of mass m2.
The forearm shown below is positioned at an angle θ with respect to the upper arm, and a 5.0-kg mass is held in the hand. The total mass of the forearm and hand is 3.0 kg, and their center of mass is 15.0 cm from the elbow. (a) What is the magnitude of the force that the biceps muscle exerts on the forearm for θ = 60°? (b) What is the magnitude of the force on the elbow joint for the same angle? (c) How do these forces depend on the angle θ ?
The small piston of a hydraulic lift has a cross-sectional area of 3.00cm^2,and its large piston has a cross-sectional area of 200cm^2.What downward force of magnitude F1 must be applied to the small piston for the lift to raise a load whose weight is Fg= 15.0kN?
The quadriceps tendon attaches to the tibia at a 30° angle 4 cm from the joint center at the knee. When an 80 N weight is attached to the ankle 28 cm from the knee joint, how much force is required of the quadriceps to maintain the leg in a horizontal position? When the subject mass is 75 kg, What is the magnitude and direction of the reaction force exerted by the femur on the tibia? (Neglect the action of other muscles.) Note: the case in static condition. Use table 4.1. wt = 80 N det = 0.28 m dy = 0.04 m R 30 80 N
A 0.150 kg frame, when suspended from a coil spring, stretches the spring 0.0400 m. A 0.200 kg lump of putty is dropped from rest onto the frame from a height of 30.0 cm (Fig.). Find the maximum distance the frame moves downward from its initial equilibrium position.
. The small piston of a hydraulic lift (g. 1) has a cross-sectional area of 3.00cm2, and its large piston has a cross-sectional area of 200cm2. What downward force of magnitude F1 must be applied to the small piston for the lift to raise a load whose weight is Fg = 15.0kN?
A 2-m long concrete traffic barrier is used to provide safety for workers, pedestrians, and motorists during highway construction. The concrete has 0.024 N/cm3 specific weight. The interface between the barrier and pavement has static and kinetic coefficients of friction of 0.45 and 0.4, respectively, and h= 45 cm. Determine the force P that will cause motion of the barrier.
The forces exerted by the bicep muscle and acting on the elbow when a 12 kg barbell is being curled can be modeled based on the diagram above. The bicep muscle can be treated as a vertical cable. The mass and length of the forearm are 2 kg and 32 cm, respectively. The center of mass of the forearm is a distance of 14 cm from the point P, while the bicep connects to the forearm at a point 4.5 cm from P. a) Determine the tension in bicep muscle and the force of the humerus acting downward on the elbow at point P. b) Assuming the tension in the bicep muscle continues to be oriented vertically, determine the tension in the bicep muscle and the force acting at P after the barbell has been raised by an angle of 30 relative to the horizontal.