Initial Tension Of Parallel Spring System

[stannard97]

Homework Statement

How to calculate initial tension or pretension in a system of two parallel springs.
F=5.33213N
K1+K2=53.0597
x=0.095

Individual springs have initial tension of 0.25N so I would expect an answer of 0.5N but I can't get there.

Homework Equations

F=(k1+k2)x

The Attempt at a Solution

Total force applied - Initial tension = (k1+k2)x
Total force applied - (k1+k2)x = Initial tension = 0.29?

 

[AlephNumbers]

Could you please restate the problem exactly as it reads? And provide a drawing perhaps? Also, I have never seen the word pretension used that way. Ever.

 

[AlephNumbers]

Those pretentious springs! Such over-inflated senses of self-worth!

 

[stannard97]

Could you please restate the problem exactly as it reads? And provide a drawing perhaps? Also, I have never seen the word pretension used that way. Ever.

Calculate the initial tension of two springs in parallel by treating them as a single spring. Initial tension as in the force needed to begin extending the spring. Ktotal is the sum of individual spring constants and total force is shared between both springs.

 

[AlephNumbers]

I would say that (k1 + k2)x - F = initial spring tension, not F - (k1 + k2)x.

 

[AlephNumbers]

Think about the initial state of the springs. The tension in them can be expressed as (k1 + k2)[x][/0] and then the force F further stretches the springs to the value (k1 + k2)x. Thus, (k1 - k2)x - F = initial tension.

 

[stannard97]

I would say that (k1 + k2)x - F = initial spring tension, not F - (k1 + k2)x.

But F_{after equilibrium}=k_total*x
where F_total is F required to overcome initial tension+Fafter equilibrium
so F_total-Initial Tension=k_total*x

 

[AlephNumbers]

Yeah that looks good. Thank you for clearly and concisely representing the quantities.