Physics

Due to the lightness of the gas bubble they feel less centrifugal force so they get collected near the neck of the bottle. They collect near the center of circular motion i.e. near the neck of the bottle.

As, the earth is not a perfect sphere, the gravity keeps on changing as we move from one place to another. But it is maximum at the place where it is nearer to the centre. So,Earth’s gravity is the maximum at the poles because the Earth is kind of an ellipse (not a perfect sphere). And the equator is further away from the centre of mass of the Earth than at the poles._x000D_ So, as we go from equator to poles, the value of g increases.

Newton’s first law is the other name of Galileo’s law of falling bodies.

Surface tension of oil is smaller than that of water. When oil is dropped on the surface of water, the force stretches the oil drops on all sides. Hence the oil spreads over the surface of water.