Question

Why does a thrown football have both potential and kinetic energy?what is the combined energy called?

Answer 1

Answer:

The thrown football has Potential or stored Energy, PE, by virtue of its position in the air and the ability for it to fall by itself. The thrown football also has Kinetic Energy, KE, given that the ball is in motion and requires an equal and opposite amount of energy to stop it. Both the PE and the KE  are forms of Mechanical Energy, ME and the Mechanical Energy of the football is equal to the sum of its Potential and Kinetic Energy. That is ME = PE + KE

Explanation:

Potential energy, PE, is the energy that is the held or stored energy of a body such that the body is able to do work without the addition of energy from an external source

A thrown football that has an elevation or height above the floor level has the capacity to come back down and bounce on the floor without the presence of assistance at the topmost height of the football. Therefore, the thrown football has potential energy, given to it by the thrower

Kinetic Energy, KE, is the energy possessed by a moving that comes from the motion of the object

Given that the thrown football is in motion, it posses kinetic energy

Therefore, the thrown football possesses both potential energy and kinetic energy which are forms of mechanical energy ME

The combined energy of the football is therefore called the Mechanical Energy ME of the ball which is the sum of the potential and kinetic energies of the football, given as follows;

The Mechanical Energy of the football = The Potential Energy of the football + The Kinetic Energy of the football

∴ ME = PE + KE