
| 1. | zero | 2. | \(-\dfrac12mu^2\cos^2\theta\) |
| 3. | \(-\dfrac12mu^2\sin^2\theta\) | 4. | \(-\dfrac12mu^2\) |
| 1. | \(\sqrt{\dfrac{k}{m}}x\) | 2. | \(\sqrt{\dfrac{m}{k}}x\) |
| 3. | \(\sqrt{\dfrac{k}{m}}(2x)\) | 4. | \(\sqrt{\dfrac{k}{m}}\left(\dfrac{x}{2}\right)\) |
| 1. | \(W_1=W_2=W_3\) | 2. | \(W_1>W_2>W_3\) |
| 3. | \(W_1>W_3>W_2\) | 4. | \(W_1<W_2<W_3\) |