are both the pistons in the same cylinder? or in two separate ones?

as per my shock analogy earlier – both are separate but joined together in series – and fixed at one end and pushed at the other !

all the suggestions so far seem to give the answer from a linear point of view, surely it's going to be on a curve?

i know the coefficient of the springs is spring is k1 and k2 and

kseries=1/k1 + 1/k2

but i dont care what the coefficient is – all i want to know is Force required to put both springs in fully compressed state and i cannot remember how to correctly relate coefficient to force – and my physics books are in storage atm !

Is propedal on or off?

haha, if only!

Trail_rat… that should be

1/Ks = 1/Ka + 1/Kb

So, if you have two springs, length l, with the same k so Ka = Kb therefore

1/Ks = 1/Ka + 1/Ka = 2/Ka

Therefore for the combined spring

Ks = Ka/2

From this we can say that if you double the length of the spring, you halve the spring rate.

And by the reciprocal of this, halve the length of the spring, double the spring rate.

Simples…

thank you funky nick.

1/Ks = 1/Ka + 1/Kb

d'oh 😳

hadn't remembered that one.

i remembered half of it 😀 – story of my university career !

obviously better than mine….