If the same student from problem 13 ran 300 m in 30 seconds the next day, by how much did her speed increase?

1.7 m/s.

Explanation:

We'll begin by calculating the current speed of the student. This can be obtained as follow:

Distance = 250 m

Time = 30 s

Speed =?

Speed = distance /time

Speed = 250 / 30

Speed = 8.3 m/s

Thus, her current speed is 8.3 m/s

Next, we shall determine the speed of the student the next day. This can be obtained as follow:

Distance = 300 m

Time = 30 s

Speed =?

Speed = distance /time

Speed = 300 / 30

Speed = 10 m/s

Thus, her speed the next day is 10 m/s

Finally, we shall determine the increase in the speed of the student. This can be obtained as follow:

Current speed = 8.3 m/s

Next day speed = 10 m/s

Increase in speed =?

Increase in speed = (Next day speed) – (Current speed)

Increase in speed = 10 – 8.3

Increase in speed = 1.7 m/s

Thus, the increase in the speed of the student is 1.7 m/s

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it

3. dark matter

empty space could also be a simple vacuum