Why is dy 0.005/2 and not 0.005 in shear stress calculation?

[goldfish9776]

Homework Statement

for the second photo , why the dy is 0.005/2 ? why not 0.005 ?

Homework Equations

The Attempt at a Solution

 

[haruspex]

Looks like a mistake to me. Also, it says acceleration where it means velocity.

 

[goldfish9776]

Looks like a mistake to me. Also, it says acceleration where it means velocity.

In your opinion , it should be 0.005 ?

 

[haruspex]

In your opinion , it should be 0.005 ?

Yes.