The most appropriate unit for expressing the speed of a space rocket is :

Options

A. `m//s`
B. `km//s`
C. `km//h`
D. `km//min`

Answer

To determine the most appropriate unit for expressing the speed of a space rocket, we can follow these steps:

### Step 1: Understand the context of the question
We need to find a suitable unit for measuring the speed of a space rocket, which travels at very high speeds compared to everyday objects.

### Step 2: Consider the options provided
The options given are:
- 1 km per second (km/s)
- 1 km per hour (km/h)
- 1 km per minute (km/min)

### Step 3: Analyze the speed of a space rocket
Space rockets travel at very high speeds. For example, a typical speed of a rocket is approximately 7.9 km per second. This means that in just one second, the rocket can travel 7.9 kilometers.

### Step 4: Evaluate the units
- **1 km/s**: This unit is suitable for high speeds, as it allows us to express the speed of the rocket in manageable numbers.
- **1 km/h**: If we were to convert 7.9 km/s to km/h, we would multiply by 3600 (the number of seconds in an hour), resulting in a very large number (28,440 km/h), which is cumbersome to express.
- **1 km/min**: Similarly, converting 7.9 km/s to km/min would also yield a large number (474 km/min), which is still not practical.

### Step 5: Conclusion
Given that rockets travel at such high speeds, the most appropriate unit for expressing the speed of a space rocket is **1 km per second (km/s)**. This unit allows for a clear and concise representation of the rocket's speed without resulting in excessively large numbers.

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