<span>They are emitted by the unstable nuclei of certain atoms.
That's all I could find out; Sorry I couldn't be more of an help.</span>
Here are the ones that I know about
and can think of just now:
-- wind
-- solar
-- nuclear
-- tidal
-- hydro
-- geothermal
-- biomass
Subjective refers to something that takes place within the mind of the person. It is modified based on individual bias.
Objective refers to defining things or expressing them without any distortion. They are expressed only as perceived.
Finally, mineral is anything composed of matter apart from animals and plants.
The speed of an object in a mass-spring system is given under the function

Here,
m = mass
k = Spring constant
A = Amplitude
x = Position
When the position is at the equilibrium point (x = 0), the speed will be maximum, and could even be expressed as

So the correct answer is B.