Answer:
The answer to the question is A.
Explanation:
The definition of moment is Force multiplied the distance to the point of interest.
So the external moment at point O is equal to ⇒ EMо= F×d
Knowing the definition of moment of inercia (I) and a newtonian Force ( m.a)
We can say that te moment of the externals force at point O is EMо= IGa
Because the rotation of a body in a inmovil point is implicated by the moment of inercia an the action of the gravity in that moment.
Answer: B
Explanation:
The reactivity of alkaline metal ( example group one ) increases down the group because of the increase in atomic mass from the top to the bottom of the group. As the mass increases, the force between the nucleus and the valence electron gets weaker and the atom will easily give up the electron as a result of this which eventually increases its reactivity.
The reactivity of halogens decreases as atomic mass increases. Therefore, option B is the correct answer.
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