What does the expression "75 meters per second southeast" best describe?

Every second this thing moves 75 meters in the southeast direction. So, 2 secons will be 150 meters, 4 seconds will be 300 meters, etc.

Southeast means something in the middle between the south direction and the east direction, maybe about - 45 degrees. We can apply Pythagorean theorem:

L1^2+L2^2=hip^2 = (75m/s) ^2

If East velocity is equal to the south velocity, both legs will be equal:

2L^2 = (75m/s) ^2

L^2 = (75m/s) ^2/2

L = square root [ (75m/s) ^2/2] = (75m/s) / [square root (2) ] = 53m/s

So the object is moving about 53m/s to the east and 53m/s to the south.

The expression "75 meters per second southeast" best describes velocity.

The beginning of the expression is providing the amount of speed of something so right away you might think that the answer is speed. Then, you read ‘southeast’ and notice the expression is also providing the direction. So, this might cause you to debate whether the answer is speed or distance, but the answer would be both. The term for an expression that is giving the speed of something and the given direction is "velocity."

- Marlon Nunez