Question

. Out of those,
wood, rock, minerals, water are natural. Human performed research on various natural
materials in laboratory. With the help of it, various materials are manufactured in factories.
Such materials are called as manmade materials. eg. Glass, plastic, artificial threads,
thermocol, etc explain in brief ​

Answer 1

Explanation:

Out of those,

wood, rock, minerals, water are natural. Human performed research on various natural

materials in laboratory. With the help of it, various materials are manufactured in factories.

Such materials are called as manmade materials. eg. Glass, plastic, artificial threads,

thermocol, etc explain in brief

Answer 2

Explanation:

Friction is a force between two surfaces that are sliding, or trying to slide, across each other. For example, when you try to push a book along the floor, friction makes this difficult. Friction always works in the direction opposite to the direction in which the object is moving, or trying to move.