Question

1. which of the following cart configurations could produce the x vs t graph shown?

Explanation:

Step1: Analyze the x - t graph

The x - t graph shows that the cart first moves in the positive x - direction, reaches a maximum position, and then moves back in the negative x - direction. This indicates that the cart experiences a force that first accelerates it in the positive direction and then decelerates it and accelerates it in the negative direction.

Step2: Analyze each option

• Option A: The configuration with the fan - cart (C) pushing in the positive x - direction initially would accelerate the cart in the positive x - direction. But without any opposing force, the cart would continue moving in the positive x - direction and not turn back as shown in the graph.
• Option B: The fan - cart (C) pushing in the negative x - direction initially would move the cart in the negative x - direction which is not consistent with the graph.
• Option C: Without any external force (no fan - cart attached), the cart would remain at rest or move with a constant velocity (if already in motion) and not show the behavior of first accelerating, then decelerating and reversing direction as in the graph.
• Option D: The two fan - carts (B and C) can be set up such that the initial net force is in the positive x - direction, accelerating the cart in the positive x - direction. Then, by adjusting the forces (for example, changing the speed or direction of one of the fans), the net force can be made to act in the negative x - direction, causing the cart to decelerate, stop, and then move back in the negative x - direction.

Answer:

D