[Q] energy transfers query

[trigger]

hi all, can anyone please tell me -- What energy transfers are used to operate a wind-up radio, from when you wind it up to listerning to the sound.

 

thanx trigger

[modest]

When a person turns their hand in a cranking motion, chemical potential energy is converted into mechanical kinetic energy by the person’s muscles. The kinetic energy is transferred to the hand crank of the wind-up radio. What happens next depends on the style of the radio:

 

Clockwork radio:

The mechanical energy of the crank is converted into elastic potential energy of a mainspring. The elastic energy of the spring is converted into mechanical energy of a rotating rotor. The rotor is part of an electric generator which converts the mechanical energy into electric energy which powers the radio. The electric energy is converted into mechanical energy by the radio’s speaker. The moving diaphragm of the speaker makes sound which we hear.

 

Rechargeable radio:

The kinetic mechanical energy of the crank is transferred to the rotor of a generator which converts the mechanical energy into electric energy. The electric energy charges a battery converting it into chemical potential energy. The chemical energy is converted into electric energy which powers the radio. The rest is the same as above.

 

The purpose of the mainspring in the clockwork radio and the battery in the rechargeable radio is to transfer energy slowly and consistently over a long period of time—just like the mainspring of a watch.

 

Energy - Wikipedia, the free encyclopedia

Clockwork radio - Wikipedia, the free encyclopedia

 

~modest

 

EDIT: It should probably be noted that a small amount of energy is converted into waste heat in all the steps above.