A contact force is a type of force which act on an object by coming in contact with the object. Examples of contact force that acts through a force field are: applied force, frictional force, air resistance force, tension, spring force, etc.
Examples of forces that act through a force field are gravitational force, electromagnetic force, the weak interaction and the strong interaction.
The moon is thought to have an iron-rich core whose radius
is 330 km, plus or minus an uncertainty of 20 km.
That puts its diameter in the range of 620 km to 700 km.
Answer: Preoperational stage (second stage).
Explanation: In the second stage of Child's development i.e., from the age of 2 years to 7 years approximately, which is called as Preoperational stage, a child develops a strong sense of Egocentrism. It is a situation where a child is unable to see thing from other peoples' eye and feels that everyone's reaction to something should be same as the child's. At this stage, a child is busy and completely trapped in his own dreamy world and is not ready to understand things properly.
Hence, the stage is Preoperational stage.
Answer:
4 decreasing energy of a closed system
