Which of the following cannot be speed-time graph of a body in motion?

Options

A.
B.
C.
D.

Explanation

To determine which of the provided graphs cannot represent a speed-time graph of a body in motion, we need to analyze the characteristics of speed and how it is represented on a graph.

### Step-by-Step Solution:

1. **Understand the Axes**:
- Speed is plotted on the y-axis, and time is plotted on the x-axis.
- Speed cannot be negative; it can only be zero or positive.

2. **Examine Each Graph**:
- **Graph 1**: The graph starts at speed 0, then increases, and later decreases. This is possible as speed can increase and decrease over time.
- **Graph 2**: This graph shows two different speeds at the same time. For a given time \( t \), if the graph intersects the vertical line at two points, it implies that the body has two different speeds at that moment, which is not possible. A body can only have one speed at any given time.
- **Graph 3**: The speed starts at a certain value and decreases over time. This is also possible as speed can decrease.
- **Graph 4**: The speed starts at zero and increases as time progresses. This is a valid representation of motion.

3. **Identify the Invalid Graph**:
- From the analysis, **Graph 2** is the only graph that cannot represent a speed-time graph because it suggests that a body has two speeds at the same time, which is impossible.

### Conclusion:
The graph that cannot be a speed-time graph of a body in motion is **Graph 2**.

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