A weightlifter is holding a biceps curl with a 300 Nbarbell at 90∘ of elbow flexion. The moment arm of the barbell about the elbow joint is 50 cm. The moment arm of the elbow flexor muscles is 6 cm. The mass of the forearm (everything from the elbow to the finger tips) is 15 kg, with a moment arm of 25 cmabout the elbow joint. How much force must be produced by these museles to hold the 300 Nbarbell in static equilibrium? Be sure show all your work.

A weightlifter is holding a biceps curl with a 300 Nbarbell at 90∘ of elbow flexion. The moment arm of the barbell about the elbow joint is 50 cm. The moment arm of the elbow flexor muscles is 6 cm. The mass of the forearm (everything from the elbow to the finger tips) is 15 kg, with a moment arm of 25 cmabout the elbow joint. How much force must be produced by these museles to hold the 300 Nbarbell in static equilibrium? Be sure show all your work.

University Physics Volume 1

18th Edition

ISBN:9781938168277

Author:William Moebs, Samuel J. Ling, Jeff Sanny

Publisher:William Moebs, Samuel J. Ling, Jeff Sanny

Chapter12: Static Equilibrium And Elasticity

Section: Chapter Questions

Problem 24P: When tightening a bolt, you push perpendicularly on a wrench with a force of 165N at a distance of...

See similar textbooks

Similar questions

Bugs Bunny, during his training for the Space Jam sequel, is trying to perform a biceps curl and is attempting to lift a 150 N dumbbell. The moment arm of this weight about his elbow joint is 25 cm. The force created by the elbow flexor muscles is 2000 N. The moment arm of the elbow flexor muscles is 2 cm. Is Bugs able to lift the weight with this amount of force in his flexor muscles?
Cole is trying a biceps curl and attempting to lift a 150 N dumbbell. The moment arm of this weight about his elbow joint is 25 cm. The force created by the elbow flexor muscles is 2000 N. The moment arm of the elbow flexor muscles is 2 cm. Is Cole able to lift the weight with this amount of force in his flexor muscles?
If the biceps brachii, attaching to the radius 2.5 cm from the elbow joint, produces 250 Nof tension perpendicular to the bone, and the triceps brachii, attaching 3 cm away fromthe elbow joint, exerts 200 N of tension perpendicular to the bone, how much net torqueis present at the joint? Will there be flexion, extension, or no movement at the joint? Is thetorque concentric or eccentric?
The maximum mass mm that a person can hold in a hand when the arm is positioned with a 105∘∘ angle at the elbow as shown in (Figure 1) is 23 kgkg . Assume the forearm and hand have a total mass of 2.0 kgkg with a CG that is 15 cmcm from the elbow, and that the biceps muscle attaches 5.0 cmcm from the elbow.
Approximately what magnitude force, FM, must the extensor muscle in the upper arm exert on the lower arm to hold a 4.3-kg shot put (Figure 1)? Assume the lower arm has a mass of 3.0 kg and its CG is 13 cm from the elbow-joint pivot.
Unlike most of the other muscles in our bodies, the masseter muscle in the jaw, as illustrated in the figure, is attached relatively far from the joint, enabling very large forces to be exerted by the back teeth. This is shown in the figure below, where a person is biting down on a bullet placed between the back teeth. (FM= 210 N and rR = 4.1 cm.) (a) Using the information in the figure, calculate the magnitude of the force exerted by the teeth on the bullet. (b) Calculate magnitude of the force on the joint.
When you lift an object by moving only your forearm, the main lifting muscle in your arm is the biceps. Suppose the mass of a forearm is 1.30 kg . If the biceps is connected to the forearm a distance dbiceps = 3.00 cm from the elbow, how much force Fbiceps must the biceps exert to hold a 750 g ball at the end of the forearm at distance dball = 35.0 cm from the elbow, with the forearm parallel to the floor? How much force Felbow must the elbow exert? (Figure 1)
When you lift an object by moving only your forearm, the main lifting muscle in your arm is the biceps. Suppose the mass of a forearm is 1.30 kg . If the biceps is connected to the forearm a distance dbiceps = 3.00 cm from the elbow, how much force Fbiceps must the biceps exert to hold a 750 g ball at the end of the forearm at distance dball = 35.0 cm from the elbow, with the forearm parallel to the floor? How much force Felbow must the elbow exert? What is the horizontal distance dforearm between the elbow and the point where the weight of the forearm acts?
Unlike most of the other muscles in our bodies, the masseter muscle in the jaw, as illustrated in the figure, is attached relatively far from the joint, enabling very large forces to be exerted by the back teeth. This is shown in the figure below, where a person is biting down on a bullet placed between the back teeth. (FM = 295 N and rR = 4.0 cm.) (a) Using the information in the figure, calculate the magnitude of the force exerted by the teeth on the bullet._________ N(b) Calculate magnitude of the force on the joint._________ N
A 72.0 kg weightlifter doing armraises holds a 7.50 kg weight.Her arm pivots around theelbow joint, starting 40.0° belowthe horizontal (Fig.).Biometric measurements haveshown that, together, the forearmsand the hands account for 6.00%of a person’s weight. Since theupper arm is held vertically, thebiceps muscle always acts verticallyand is attached to the bonesof the forearm 5.50 cm from theelbow joint. The center of mass of this person’s forearm–hand combinationis 16.0 cm from the elbow joint, along the bones of the forearm,and she holds the weight 38.0 cm from her elbow joint. (a) Draw a freebodydiagram of the forearm. (b) What force does the biceps muscleexert on the forearm? (c) Find the magnitude and direction of the forcethat the elbow joint exerts on the forearm. (d) As the weightlifter raisesher arm toward a horizontal position, will the force in the biceps muscleincrease, decrease, or stay the same? Why?
During most of the stance phase of the gait, the knee flexion is less than 20º. What force must the quadriceps muscle apply to maintain this flexion while standing on one leg? The patient's weight is 836N, assuming that the distance from the center of the joint to the line of gravity is 5 cm and the distance perpendicular to the center of the joint towards which the muscle acts is 5 cm, and the muscle acts ( pull) at 60º to the horizontal.
While doing a back squat, you're doing reps with 300 pounds on the barbell (total mass of the barbell and weights; you're strong...you got this!). At the bottom of your squat, your hip is flexed to a 45deg angle, your knee is flexed to a 90deg angle, and your ankle is dorsiflexed to 75deg. The force vector of the barbell is 15cm anterior from the hip joint, 20cm posterior from the knee joint and 12cm anterior from the ankle joint. How much torque is the barbell applying to the hip joint? 138.29Nm extension torque 160.53Nm extension torque 200.66Nm flexion torque News team....ASSEMBLE!!!!!! O 267.55 Nm flexion torque