ANS:C - form

Friction produced by the formation of wakes is called form friction. Here's an explanation:

• Form Friction: In fluid dynamics, form friction refers to the resistance or frictional drag caused by the formation of wakes and eddies around a body moving through a fluid. When a solid object moves through a fluid, it disturbs the flow, creating regions of turbulence and vortices (wakes). These wakes induce additional drag force on the body, which is known as form friction.
• Disk Friction: Disk friction typically refers to the frictional resistance between two sliding or rotating solid surfaces, often in mechanical systems.
• Skin Friction: Skin friction (also called viscous friction) is the resistance to the movement of a fluid over the surface of a solid object due to the viscosity of the fluid.
• None of these: This option would imply that there is another specific term for the friction produced by the formation of wakes, which isn't the case as form friction accurately describes this phenomenon.