Energy can be considered as stored force. It a bow is pulled tight , for example, force is needed to do this. This force is stored as energy in the bow: since the bow is elastic, it will shoot back to its old form when it is released (this energy is called potential energy) . The energy is transformed to an arrow that is placed in the bow, and the string is dawn back. As soon as the string is released, the arrow is accelerated and kinetic energy is given to it. if the arrow is shot vertically into the air, its kinetic energy decreases as it flies higher due to the gravitational pull of the Earth. It will stop for a bit of second in its apparent position However the energy is not vanished it get converted into potential energy for some second and the gravitational pull for Earth start pulling it and the potential energy again get converted into Kinetic energy, The higher the arrow was shot into the air in first place, the faster it will be travelling when it reaches the ground again , such a way the energy get converted into different forms.