Calculating the Force of the Deltoid Muscle to Raise an Arm

In summary: So i decided to come at this from another angle. First i solved for Fg,Fg=1.57*9.8 = 15.39Then to solve for Fm,Fm=15.39cos 13.2 = 14.98But the correct answer is 67.38. I am not sure where to go from here to get the correct answer. Any help would be appreciated. Thanks:smile:
  • #1
Eggphys
12
0

Homework Statement


The main muscle responsible for raising an arm is the deltoid. The deltoid muscle connects at the upper end of the shoulder, extends over the upper arm bone (humerus), and attaches near the elbow. Effectively there are three forces involved in raising the arm: (i) the force of the deltoid muscle, Fm, acting at an angle of approximately 13.2o with respect to the negative x axis, (ii) the force of gravity, Fg, acting effectively at the centre of mass of the arm located close to the elbow, and (iii) the force of the shoulder socket, Fs, acting on the humerus effectively along the x axis. Assuming the mass of the arm is 1.57 kg, calculate the magnitude of Fm in Newton.




Homework Equations


[tex] F=ma [/tex]



The Attempt at a Solution


I'm not quite sure where to start. I tried using [tex] F_x=ma [/tex] and [tex] F_y=ma [/tex] to work out the net force but not getting the correct answer. Any help would be greatly appreciated. Thanks.
 

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  • #2
Sorry I made a mistake you can do it with just Newtons law no torques needed . Can you show your actual work force decomposition should work if you didn't do any calculation mistakes?
 
Last edited:
  • #3
bp_psy said:
Sorry I made a mistake you can do it with just Newtons law no torques needed . Can you show your actual work force decomposition should work if you didn't do any calculation mistakes?
After going over my work abit more I see I have no clue what I am doing:frown:
Im not sure how to implement the angle into the equation or what a is in the x direction(Isnt it 0?)
Would Fy just be Fy=1.56*9.8?
Any help on where to start would be great. Thanks:smile:
 
  • #4
Eggphys said:
After going over my work abit more I see I have no clue what I am doing:frown:
Im not sure how to implement the angle into the equation or what a is in the x direction(Isnt it 0?)
Would Fy just be Fy=1.56*9.8?
Any help on where to start would be great. Thanks:smile:

So i decided to come at this from another angle. First i solved for Fg,
Fg=1.57*9.8 = 15.39
Then to solve for Fm,
Fm=15.39cos 13.2 = 14.98

But the correct answer is 67.38. I am not sure where to go from here to get the correct answer. Any help would be appreciated. Thanks:smile:
 
  • #5
Just bumping back to the top.
 

FAQ: Calculating the Force of the Deltoid Muscle to Raise an Arm

1. How is the force of the deltoid muscle calculated?

The force of the deltoid muscle can be calculated using the equation F = ma, where F is the force, m is the mass of the arm, and a is the acceleration of the arm. The acceleration of the arm can be determined by dividing the change in velocity by the time it takes to raise the arm.

2. What factors affect the force of the deltoid muscle?

The force of the deltoid muscle can be affected by several factors, including the size and strength of the muscle, the angle at which the arm is raised, and the weight of the arm. Additionally, the force can be influenced by any injuries or conditions affecting the deltoid muscle.

3. How does the force of the deltoid muscle compare to other arm muscles?

The deltoid muscle is one of the strongest muscles in the arm, responsible for lifting and rotating the arm. It is typically stronger than the biceps and triceps muscles, but not as strong as the muscles in the shoulder and chest.

4. Can the force of the deltoid muscle be improved?

Yes, the force of the deltoid muscle can be improved through regular strength training exercises targeting the deltoid muscle. These exercises can help increase muscle mass and improve overall strength and force production.

5. Are there any risks associated with calculating the force of the deltoid muscle?

There are no specific risks associated with calculating the force of the deltoid muscle, but it is important to use proper form and technique when performing any exercises or movements that target the deltoid muscle. As with any physical activity, it is always advisable to consult with a medical professional before starting a new exercise routine.

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