Question

What do we mean by 'streamlined shape'? How does it help in the motion of vehicles?

Answer 1

A streamlined body is a shape that lowers the friction drag between a fluid, like air and water, and an object moving through that fluid. Drag is a force that slows downmotion; friction drag is a special kind of drag. which affect motion and reduces speed

Airplanes are streamlined in order to reduce drag (coefficient of friction). This allows for less resistance, less fuel consumption, and greater speed. Cars have a streamlined shape because it reduces the amount of air drag / air resistance, thus allowing less amounts of energy to be wasted.