In a mechanical clock the swinging of a pendulum. causes the hands to move. the diagram shows the path of the pendulum as it swings. at which point in it's swing does the pendulum have the least gravitational potential energy?

Explanation :

We know that the kinetic energy is possessed due to motion and potential energy is possessed due to height.

When the bob of the pendulum releases, its potential energy converted into kinetic energy. Then after some time, the gravitational potential energy is converted into kinetic energy.

From the figure, it is clear that the pendulum has the least gravitational potential energy at point C.

Hence, this is the required solution.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.