A mass attached to two springs with different k values

[darrenhb]

Hey. Suppose a mass is attached to two springs, one on each side, and they have different values for k. If you wanted to measure the frequency, how would you add up the k values? Would it work as if they were in series, so 1/k = 1/k1 + 1/k2, or would it just be k = k1 + k2 like in parallel? Or something else?

Thanks!

 

[Doc Al]

See if you can figure it out. Imagine the mass pushed a distance X from equilibrium. What's the total restoring force from the two springs?

 

[darrenhb]

What I figured was that it would be F = -k1x - k2x, and therefore k = k1 + k2. Is this correct?

I always over-think these things!

 

[Doc Al]

What I figured was that it would be F = -k1x - k2x, and therefore k = k1 + k2. Is this correct?

You got it.

(Now you should figure out how things would be different if the springs were connected together in series.)

 

[darrenhb]

Thanks! I'll give that a go later, haha.