Question

exam lesson name: motion and forces
exam number: 700696rr
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question 6 of 20 :
select the best answer for the question.

1. which of the following statements is accurate?

○ a. if an object’s velocity is changing, it’s experiencing either acceleration or deceleration.
○ b. if an object is said to be decelerating, its velocity must be increasing.
○ c. if an object’s velocity decreases, then the object is accelerating.
○ d. if an object’s velocity remains constant, its acceleration must be increasing.

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Explanation:

• Analyze Option A: Acceleration is defined as the rate of change of velocity. So if velocity changes (either in magnitude or direction), there is acceleration (deceleration is a type of acceleration where velocity magnitude decreases). This statement is correct.
• Analyze Option B: Deceleration means the velocity is decreasing (magnitude), so this statement is wrong.
• Analyze Option C: If velocity decreases, the object is decelerating (a type of acceleration with negative sign, but the statement's wording is incorrect as "accelerating" in common terms for magnitude increase is wrong here).
• Analyze Option D: If velocity is constant, acceleration (rate of change of velocity) is zero, not increasing. So this is wrong.

Answer:

A. If an object's velocity is changing, it's experiencing either acceleration or deceleration.