Final answer:
None of the provided situations (A) Speeding car, (B) Remote control car, or (C) Earning money on separate days, model a sum of zero. In physics, a sum of zero is typically modeled by situations where forces or displacements cancel each other out, such as an object moving there and back along the same path, resulting in zero net displacement and, therefore, an average velocity of zero.
Step-by-step explanation:
Understanding Motion and Velocity
A student inquired about modeling a sum of zero. It appears that they are asking about situations where net changes equal zero, suggesting an understanding of balanced forces or equilibrium. The student's question, however, contains mixed contexts that may not directly relate to the principle of summing to zero. To address the original query:
(A) A car moving at 10 mph over a speed limit does not model a sum of zero. Instead, it's an example of exceeding a set velocity by a certain amount.
(B) A remote control car reaching an altitude of 11 inches is a scenario describing motion, but does not in itself suggest that a sum of zero is involved.
(C) Earning $5 on two separate days does not provide a context of opposing values that sum to zero.
If the inquiry is regarding physics and motion, it would make sense in circumstances such as a car moving in one direction, and then in the opposite direction at the same speed for the same distance, resulting in a net displacement of zero. Or in a scenario where forces acting on an object are equal in magnitude but opposite in direction, they would cancel each other out, resulting in a net force of zero. The concept of a sum of zero is also illustrated when discussing average velocity, where if an object travels out and back along the same path, the displacement is zero, thus the average velocity is zero even if the average speed is positive.
In the given examples, neither represents a literal sum of zero in the context provided. Therefore, the correct answer would be (D) None of the above.
Velocity and Physics Principles
Let's look at some principles relevant to the subject:
- When a car moves at constant speed in a single direction, the average velocity and average speed are the same, provided the car doesn't reverse its direction.
- If a car is rounding a bend at a constant speed or a merry-go-round is increasing to a constant rotational speed, these describe motion at constant velocity and increasing velocity, respectively. Neither implies a sum of zero.
- In motion, average speed is the total distance traveled divided by the elapsed time.
- The speed of a car at any given moment can be faster or slower than its average speed or might require acceleration, which is a change in speed, indicating a non-zero sum result.
- A pendulum that swings back and forth is an example of an oscillating system where kinetic and potential energies exchange, but the sum of the energies remains constant if we ignore air resistance and other dissipative forces.