35. What must be true about the cut pieces, sawdust, and original uncut board, according to the law of conservation of matter?
Answer: A
The mass of the uncut board equals the mass of the large pieces plus the mass of the sawdust.
According to the law of conservation of matter, the total mass of the system must remain constant. Therefore, the mass of the original uncut board is equal to the combined mass of the cut pieces and the sawdust produced during the cutting process.
A) The mass of the uncut board equals the mass of the large pieces plus the mass of the sawdust.
This option accurately reflects the law of conservation of matter. When the board is cut, the mass is neither created nor destroyed; it is simply redistributed among the large pieces and the sawdust. Thus, the total mass remains constant, confirming this option as correct.
B) The total mass of the sawdust equals the mass of the large pieces.
This statement is incorrect because it ignores the mass of the original uncut board. While the sawdust and the large pieces do have mass, their combined mass must also account for the original board's mass, making this option inconsistent with the law of conservation of matter.
C) The mass of the uncut board equals the total mass of the large pieces.
This option is incorrect as it fails to consider the mass of the sawdust generated during the cutting process. The law of conservation of matter states that all mass must be accounted for, including that of the sawdust.
D) The total mass of the sawdust equals the mass of the large pieces minus the mass of the uncut board.
This statement is fundamentally flawed because it presents an incorrect relationship between the masses. It suggests that the mass of the sawdust can be derived by subtracting the mass of the uncut board from the mass of the pieces, which contradicts the conservation principle and does not hold true in this context.
Conclusion
The correct answer, option A, aligns perfectly with the law of conservation of matter, illustrating that the total mass remains unchanged throughout the cutting process. All other options fail to accurately represent the relationship among the mass of the uncut board, the large pieces, and the sawdust, thereby violating the principle that mass is conserved in a closed system.