Spring and string pendulum (oscillations)

[haruspex]

@haruspex I imagine so since it was a problem at a real exam a couple of years ago. Well I read the problem again and nothing's stated about t=0 until question c) and it is unfortunately for α = 0 then.

Yes, my remark about t=0 was only in relation to part c.
For part b, the only other suggestion I have is that it should say to find α_R in terms of m, L, k and x₀.

 

[JulienB]

Also, if I assume that α(0) = α_R, I think it implies that B = 0.

 

[JulienB]

Yes, my remark about t=0 was only in relation to part c.
For part b, the only other suggestion I have is that it should say to find α_R in terms of m, L, k and x₀.

Yes and that could be easily done with the force equation right? Well, thank you for your help in any case! Was my reasoning in part c) coherent?Julien

 

[haruspex]

Yes and that could be easily done with the force equation right? Well, thank you for your help in any case! Was my reasoning in part c) coherent?Julien

In the equation you posted for α'(0) you had a sign wrong, but that must have been a mistake in typing the post since the answer you got is right.