Answer:
1.If one drops a stone into a pond, a very rapid, thin jet of water spouts upwards. A cavity forms behind the object during impact on the water surface. This cavity is subsequently compressed by hydrostatic pressure, which leads to the formation of the jet.
2.Ripples are the instant effect of wind on water and they die down as quickly as they form, as the surface tension of the water dampens their efforts. If a wind blows steadily across a large enough patch of water for a few hours then the ripples become waves and these will not be dampened so easily.
3.When you throw a rock into a river, it pushes water out of the way, making a ripple that moves away from where it landed. As the rock falls deeper into the river, the water near the surface rushes back to fill in the space it left behind.