Awater tunnel has a circular cross-section with a radius of 1.8 m in its main section. in a test section of the tunnel the radius constricts to a value of 0.60 m. if the speed of water flow is 3.0 m/s in the main section, determine the speed of water flow in the test section.

To solve this problem it is necessary to apply the concepts related to the concepts to continuity.

From the continuity equation we know that

Where,

A = Cross-sectional Area

V = Velocity

In a circle the area is given by

Therefore replacing with our values we have that

While the area two is defined as

Applying the continuity equation we have to

Therefore the speed of water flow in the test section is 27.28m/s

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)