Final answer:
To calculate the time it takes for the nitrogen molecule to cover 20 km, divide the distance by the average speed and convert the time from seconds to minutes. The molecule will take approximately 0.647 minutes to travel 20 km.
Step-by-step explanation:
The student is asking how long it will take for a nitrogen molecule moving at an average speed of 515 m/s to cover a distance of 20 km. To solve this, one would use the formula for time, which is distance divided by speed. The distance (20 km) needs to be converted into meters (20,000 m) to match the units of speed (m/s).
Time = Distance / Speed
Time = 20,000 m / 515 m/s
Time ≈ 38.835 s
Since the student asked for the time in minutes, we must convert seconds to minutes by dividing by 60.
Time in minutes = 38.835 s / 60
Time in minutes ≈ 0.647 minutes
Hence, it will take approximately 0.647 minutes for the nitrogen molecule to travel 20 km.