Final answer:
The question appears to be about finding the negative root or -y for a given function. However, the context is unclear, which makes providing a direct solution challenging. The general principle is that for any positive number 'a', there is a negative square root -√ a, but for a negative number, the square root is not defined in real numbers.
Step-by-step explanation:
The student's question seems to contain multiple parts, and the directive to 'solve for -y' isn't clear in the context of the information given. However, since the initial part of the question refers to y = square root of (2-x), and a subsequent solution discusses the selection of a negative root (which is -5.42 m/s), we can address the question of finding the value of -y.
For a positive number 'a', there are two square roots, one positive (√ a) and one negative (-√ a). In physical contexts like velocity, a negative root can indicate a direction opposite to the one defined as positive. When the value inside the square root (the radicand) is negative (e.g., √-3), assuming we are not dealing with complex numbers, there is no real number solution because the square root of a negative number is undefined in the real number system.