Questions

Lithium is the lightest of all the metals due to its low atomic number among metals. It is the lightest solid element.

Properties ::

* It is a soft silvery-white alkali metal.

* Lithium is highly reactive and flammable and is stored in mineral oil.

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Those are stairs which goes up and down without moving.

Parabola, because when the coin is dropped at a particular point, it has the same velocity as the running train. So, by Newton's first law, it continues its motion horizontally with that velocity. But then, it is also pulled down by earth's gravity continuously. In this situation its horizontal motion gives way to the parabolic motion until it reaches the ground.