Question:
Answer:
My Problem:
I don't understand what they have done in the mark scheme where I have put a red box around the part that I don't understand. Please help. Thanks in advance.
The strings elongate right? Those strings contain elastic potential energy. For calculation purposes, read Young's modulus - Wikipedia, the free encyclopedia
Oh, I see. Thanks.
I thought they were using $\displaystyle \mathrm{KE}_{\mathrm{GAIN}} = \frac12 m (v^2 - u^2)$ which got me confused. I believe $\displaystyle u$ is zero hence $\displaystyle u^2$ is zero? If it was a value, would it be $\displaystyle \frac12 m (v^2 - u^2) + \frac{\lambda x^2}{2l} = mgh$?