The parabolic shape of the cables along suspensionbridges help carry the forces acting on the bridgeto the top of the towers (which can usually standflexing, buckling, and oscillation)
Everything on the planet Earth is subject to gravity. When on object is thrown or forced in a direction not on the ground, eventually gravity grabs it and drags it down. The path the object follows it that of a Parabola.
Galileo found that all objects thrown form a parabolicpath, no matter what. He deduced this by the simpleobservation of watching objects being thrown. Galileois responsible for the modern concepts of velocity andacceleration to explain projectile motion that isstudied today:A projectile which is carried by a uniform horizontal motioncompounded with a naturally accelerated vertical motiondescribes a path which is a semi-parabola.
Heaters are sold which make use of the relection property of the parabola. The heat source is at the focus and heat is concentrated in parallel rays.
A person who whispers at the focus of one of the parabolic reflectors can be heard by a person located near the focus of the other parabola.