Jason is trying out different methods of folding paper airplanes to fly them as far as possible. He tells Brian, his brother, he is going to try making the wings much more narrow. Brian tells him smaller wings will make it fly a much shorter distance, but Jason disagrees. Who is correct and why?

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa.s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)