Question

A train travels in a straight line at 18.0 m/s for 2 km, then at
30.0 m/s for another 2 km.
Is the average speed greater than, less than, or equal to 25m/s

Answer 1

Answer:

It is less than 25m/s as the correct average is 24m/s.

Explanation:

This is becuase you need to take the average of the two speeds (18m/s and 30m/s) 18 + 30 divided by 2 is 24m/s.

Answer 2

First, the train travels at 18 m/s for (2000/18) seconds.

Then it travels at 30 m/s for (2000/30) seconds.

Average speed = (total-distance)/(total-time)

Total distance = 4000 meters

Total time = (2000/18 + 2000/30) s

That's (10,000/90 + 6,000/90)

That's (16,000/90) or (1600/9) sec

Average speed = (4000•9/1600) m/s

Average speed = 22.5 m/s

That speed is LESS THAN 25 m/s .