How Does the Force of a Helical Spring Impact Barbell Stability?

[blackbrella]

Homework Statement

The project i am working on is determining the force of a helical spring on a barbell. Like this (http://bodybuilderfitness.com/library/2York_Barbell_Spring_Collar_Side_View.JPG" .

Once i find the amount of force the on the barbell via the spring collar, i need to find how much weight (free weights in 25 kg increments) & and what angle is needed overcome the friction and spring collar force.

I am not sure what equations i need to use exactly. To solve this let's make a few assumptions.

I think the angular spring rate tells me how much force is on the bar, maybe?

50 kgs of Iron weights on each side of the barbell
A steel spring, E=28Mpsi, G=10Mpsi
Angle of Barbell = 30 deg
mu of iron on steel = 0.4 static, 0.23 sliding
spring handles are 2" long
Diameter outer of spring, Do = 1.5"
diameter of the wire, d = 0.2"
# body coils, Nb (before handles are squeezed which increases the number of coils) = 4.375

Homework Equations

**i think the angular spring rate is what tells me how much force is on the bar

force on barbell via spring:
mean diameter, D = Do-d
angular spring rate, ko = M/deg,rev = (E*d^4)/(10.186*D*Na)
# of active coils, Na = Nb + Ne
# of end coils, Ne = (l1 +l2)/(3*pi*D)

sliding weights:
F=m*g*mu,static*cos()

I am sure i am missing a lot and maybe chose wrong eq's.

The Attempt at a Solution

Ne = 0.33
Na = 4.7
ko = 719.61 psi

F@30deg = 547.352 (units? ft/s^2?)

my assumption on angular spring rate is assuming the force it takes to open the spring wider (squeeze handles) is then applied onto the bar because it cannot return to its original size.

 

[LightHero]

Is this accurate?To overcome the force of the spring collar, we need to add a weight of 50 kg on each side of the barbell. This will provide a static friction force (F=m*g*mu,static*cos(30)) of approximately 1497 N. The total force required to overcome the spring collar is then 547.352 + 1497 = 2044.352 N.

 

[Mene]

it is important to carefully consider the assumptions and equations used in any experiment or project. In this case, it appears that you are using the angular spring rate to determine the force on the barbell via the spring collar. However, it is important to note that the angular spring rate may not accurately represent the force on the barbell as it is dependent on the materials and dimensions of the spring. It may be more accurate to use Hooke's Law, which states that the force exerted by a spring is directly proportional to the displacement of the spring from its equilibrium position.

Additionally, it is important to consider the effects of friction in your calculations. The friction between the weights and the barbell may impact the force required to overcome the spring collar force. It may be helpful to incorporate the coefficient of friction into your equations.

Overall, it is important to carefully consider all variables and assumptions in your project and to use appropriate equations to accurately determine the force on the barbell. Further research and experimentation may be necessary to ensure the accuracy of your results.