Question

1 which of the following boxes are not moving? images of boxes a, b, c, d, e with arrows indicating forces; multiple-choice options: d a, c b, b c, e d, a e

Explanation:

Step1: Analyze Box A

Box A has arrows in four directions (up, down, left, right). This suggests balanced forces? Wait, no—wait, the question is about not moving. Wait, maybe the arrows represent movement directions? Wait, no, maybe the number of arrows? Wait, Box B: left and right arrows (2 arrows). Box C: left, right, down (3 arrows). Box D: left, right, up (3 arrows). Box E: left, right, up, down (4 arrows). Wait, no, maybe the key is that for a box to not move, the horizontal and vertical forces are balanced? Wait, Box B: only horizontal arrows (left and right), so vertical forces? Wait, maybe the number of arrows in each direction. Wait, Box A: 4 arrows (up, down, left, right) – balanced? Box B: 2 arrows (left, right) – vertical? Wait, no, maybe the correct approach is to see which boxes have equal number of arrows in opposite directions. Wait, Box B: left and right (2 arrows, equal), no vertical arrows – so vertical forces? Wait, maybe the problem is about balanced forces (Newton's first law: if net force is zero, object is at rest or moving at constant velocity). So for each box, check if horizontal and vertical forces are balanced.

- Box A: Arrows up, down, left, right. So up and down: 1 each (balanced), left and right: 1 each (balanced). Net force zero? Wait, no, maybe the number of arrows. Wait, Box A: 4 arrows (up, down, left, right). Box B: 2 arrows (left, right). Box C: 3 arrows (left, right, down). Box D: 3 arrows (left, right, up). Box E: 4 arrows (left, right, up, down). Wait, maybe the boxes that have equal number of arrows in horizontal and vertical directions? Wait, Box B: only horizontal (left, right) – vertical arrows? No. Wait, maybe the answer is Box B? Wait, no, let's re-examine the options. The options are D A, C B, B C, E D, A E. Wait, the question is "Which of the following boxes are not moving?" Wait, maybe the boxes with balanced forces (net force zero) are not moving. Let's check each box:

- Box A: Arrows in all four directions (up, down, left, right). So up and down forces: 1 each (balanced), left and right: 1 each (balanced). Net force zero? So not moving?
- Box B: Arrows left and right (2 arrows). No vertical arrows. So vertical forces? If there are no vertical arrows, maybe vertical forces are balanced (e.g., gravity and normal force), but horizontal: left and right (balanced). So net force zero?
- Box C: Arrows left, right, down (3 arrows). Up arrow? No. So vertical forces: down (1) and up (0) – unbalanced. So moving?
- Box D: Arrows left, right, up (3 arrows). Down arrow? No. Vertical forces: up (1) and down (0) – unbalanced. Moving?
- Box E: Arrows left, right, up, down (4 arrows). Up and down: 1 each (balanced), left and right: 1 each (balanced). Net force zero? Not moving?

Wait, but the options are combinations: D A, C B, B C, E D, A E. Wait, maybe the boxes with balanced forces (net force zero) are A, B, E? But the options are pairs. Wait, maybe I misinterpret the arrows. Maybe the arrows represent the direction of movement, and a box not moving has no arrows? No, all boxes have arrows. Wait, maybe the number of arrows: Box B has 2 arrows (left, right), Box C has 3, Box D has 3, Box A has 4, Box E has 4. Wait, the options: Let's look at the option "B C" – no, Box C is moving. "A E" – Box A and E have 4 arrows (balanced), Box B has 2 (balanced). Wait, maybe the correct answer is the pair where both boxes have balanced forces. Box B: left and right (balanced), no vertical arrows (so vertical forces balanced). Box A: all four directions (balanced). Box E: all four directions (balanced). Wait, the option "A E" is one of the choices (the last option: A E). Wait, let's check the option labels: the top options are D A (first), C B (second), B C (third), E D (fourth), A E (fifth). So the fifth option is A E. Let's confirm:

- Box A: 4 arrows (up, down, left, right) – balanced, not moving.
- Box E: 4 arrows (up, down, left, right) – balanced, not moving.
- Box B: 2 arrows (left, right) – balanced horizontally, vertically? If no vertical arrows, maybe vertical forces are balanced (e.g., stationary on a surface, gravity and normal force), so Box B is also not moving? Wait, but the option A E is there. Wait, maybe the key is that Box A and E have arrows in all four directions (balanced), Box B has two (balanced), but the option A E is present. Alternatively, maybe the boxes with equal number of arrows in each axis: Box A (4 arrows: 2 horizontal, 2 vertical), Box E (4 arrows: 2 horizontal, 2 vertical), Box B (2 arrows: 2 horizontal). So Box A, B, E are not moving? But the options are pairs. The option A E is an option (last one: A E). So I think the correct answer is A E.

Step2: Confirm the Option

Looking at the options, the fifth option is "A E" (the last box with E and A). So the boxes A and E have balanced forces (arrows in all four directions, so net force zero) and thus are not moving.

Answer:

A. E A (Wait, no, the option is labeled as "A E" in the fifth position: the last option is "A E" with E and A? Wait, the top options: first is D A (box D and A), second C B (C and B), third B C (B and C), fourth E D (E and D), fifth A E (A and E). So the correct option is the fifth one: A E.