What is meant by "elastic collisions?

When a moving car hits a parked car, causing the parked car to move, the type of collision is elastic collision. An elastic collision is when two bodies collide and separates after collision conserving the total kinetic energy before and after collision.

when earth is in rotational motion around the sun,it displaces from its place.

when a ball is placed on an inclined surface it does both the rotational and circular motion.

explanation:

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods