Amplitude of SHM of a spring hung from a ceiling

[Vriska]

Homework Statement

A point mass of m = 20 kg is suspended by a massless of constant 2000N/m. The point mass is released when the elongation is 15cm.Find equation of shm

Homework Equations

F= - kx

The Attempt at a Solution

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I'm not sure what this question is trying to say honestly. But - I'd say the mean position would be at x = 10 cm and since they release it at 15 cm, I'd expect the amplitude to be 5 cm.

But they've said the amplitude is A = mg/x in the answer , which I don't quite process. And they've done something and found the phase to be off by pi/6. Is this just a badly worded question or am I wooshing somewhere?

 

[Doc Al]

Is this just a badly worded question

I'd say it's a badly worded question (or an error in the answer key). Is it from a textbook?

 

[Vriska]

I'd say it's a badly worded question (or an error in the answer key). Is it from a textbook?

It's from a workbook for an exam :/ thanks for confirming my suspicions though, I've already seen quite a few badly worded problems here and suspected this might also be one

 

[Doc Al]

But they've said the amplitude is A = mg/x in the answer

That expression doesn't even have the correct dimensions for an amplitude. (Unless that x was meant to be a 'k'.)