Question

which of these dot diagrams best describe the motion of a free-falling object that is dropped from rest? tap to select or deselect an answer. diagram a diagram b diagram c

Explanation:

Step1: Recall free - fall motion

A free - falling object (dropped from rest) accelerates due to gravity. The distance it travels in successive equal time intervals increases because the velocity is increasing ( \(v = u+gt\), where \(u = 0\) for an object dropped from rest, so \(v=gt\), and the distance \(s=ut+\frac{1}{2}gt^{2}=\frac{1}{2}gt^{2}\)). So, in dot - diagrams representing the motion, the spacing between the dots (which represent the position of the object at equal time intervals) should increase as time progresses (as the object falls down).

Step2: Analyze each diagram

• Diagram A: The dots are getting closer together as we move from left to right. This would represent a decelerating motion, which is not free - fall (since free - fall is accelerating).
• Diagram B: The dots are getting farther apart as we move from left to right. This is consistent with an object accelerating (like a free - falling object) because in each successive equal time interval, the object travels a greater distance.
• Diagram C: The dots are equally spaced, which represents a constant - velocity motion (uniform motion), not an accelerating motion like free - fall.

Answer:

B. Diagram B