Final answer:
The difficulty in Part B relates to accurately measuring small masses and the weak gravitational forces they exert, requiring sensitive equipment and careful methods. The description process appears to relate to a variable that decreases over time. Clear and specific language is imperative for effective descriptions in scientific contexts.
Step-by-step explanation:
To address the question in Part B on why it was difficult in terms of the masses used in the apparatus and the strength of the gravitational force, we need to consider the principles of physics. The difficulty may arise due to the precise requirement of measuring very small masses or because the gravitational force, which is proportional to the mass of the objects, can be weak and hard to measure accurately.
When working with smaller masses, the gravitational forces involved are also smaller and thus, more sensitive equipment and careful methods are needed to obtain accurate results. This complexity is compounded by variations in local gravitational strength due to factors such as altitude and Earth's varying density.
The description in Part A suggests a graph of a variable that starts at a nonzero value and then decreases, potentially indicating a process involving decay or depletion over time. Without additional context, however, it's difficult to provide a complete analysis.
When answering questions about observational and descriptive skills, it's important to articulate your descriptions clearly and use specific language so that your classmates can understand and identify the samples described. This descriptive skills component is essential in the fields of science and engineering where accurate and detailed descriptions lead to better understanding and replication of experiments.