[erickejah (OP)]

What do you think that mechanical resonance is?  Do you think of a good example to share with us?

Does our body produce any form of mechanical resonance?

Is mechanical resonance used to start radioactivity?

[RD]

a good example [of mechanical resonance] to share with us?

The mirror on a motorbike I had would noticeably vibrate (blurring the image) when the engine was at a particular rpm,
 when the engine revs were above or below that level the mirror was static.

[syhprum]

Our perception of sounds depends on a resonant structure in the inner ear the cochlea, this is a spiral structure with a series of hair like resonators that acts in a similar way to a spectrum analyser sending a frequency analysis of the sound waves to the brain.

[Soul Surfer]

Resonance can occur in any process where there is a reversible process for transferring energy between two energy stores.  In mechanical processes this is usually between potential energy and kinetic IE the height and the velocity of a swing or pendulum or the tension and speed of a spring or tuning fork.  in electromagnetics it is usually between charge stored in a capacitor and magnetic field stored in an inductor.

to get a good resonance the amount of energy lost per cycle of motion must be minimised  this property is called the Q factor and the larger it is the less energy is lost each cycle.

[erickejah (OP)]

Thanks , I am still wondering if radioactivity is (can be) started by resonance of molecules...

[Madidus_Scientia]

When you push someone on a swing, you are providing a resonating force, you wait until they are back near you before you push again. If you pushed them twice as frequently they wouldn't swing as far.