Question

image result for velocity vs. time graphs which of the velocity vs. time graphs above represents an object that moves with a constant positive velocity, then suddenly stops and moves in the opposite direction with a negative velocity? 1 ○ 3 2 4

Explanation:

To determine the correct velocity - time graph, we analyze the motion:

1. Constant positive velocity: On a velocity - time graph, a constant velocity is represented by a horizontal line above the time axis (since velocity is positive).
2. Suddenly stops: This would be represented by the velocity dropping to zero (the graph touches the time axis) instantaneously (a vertical or near - vertical drop, but in idealized graphs, a sharp change to zero velocity).
3. Moves in the opposite direction with negative velocity: After stopping, the velocity becomes negative, so the graph should be a horizontal line below the time axis.

We assume that graph 3 (the one with the selected circle) follows this pattern: first a horizontal line in the positive velocity region, then a sharp drop to zero, and then a horizontal line in the negative velocity region. The other graphs (1, 2, 4) do not match this sequence of motions. For example, a graph with only positive velocity or a graph that does not have the correct transition from positive to zero to negative velocity can be eliminated.

Answer:

3 (the graph labeled 3, with the circle indicating selection, represents the object's motion: constant positive velocity, sudden stop, then negative velocity motion)