Additional Questions With Solutions:
Ques: Define force.
Ans: A push or a pull on an object is called a force.
Ques: Define muscular force.
Ans: The force resulting due to the action of muscles is known as the muscular force.
Ques: Write the kinds of force.
Ans: There are two kinds of force.
(i) Contact force
(ii) Non-contact force
Ques: What is contact force? Write its types.
Ans: Muscular force can be applied only when it is in contact with an object, it is also called a contact force.
This is two types:
(i) Muscular force – The force resulting due to the action of muscles is known as the muscular force.
(ii) Frictional force - The force acts opposite to the direction of motion and this is responsible for changing the state of motion of objects. It arises due to contact between the surfaces.
Ques: Why is frictional force known as contact force?
Ans: The frictional force known as contact force as it arises due to contact between the surfaces.
Ques: What is non-contact force? Write its types.
Ans: The force which is felt by the objects without any contact is known as non-contact force.
This is two types:
(i) Electrostatic force: The force exerted by a charged body on another charged or uncharged body is known as electrostatic force.
(ii) Gravitational force: Every object attracts each other and pulls toward itself. Such force which applied on objects is known as Gravitational force and gravitation
Ques: Define Pressure.
Ans: The force acting on a unit area of a surface is called pressure.
Ques: Why shoulder bags are provided with broad straps and not thin strap?
Ans: Broad straps reduce pressure on back. If the strap will be thin the value of pressure will be raised as per unit area of surface gets reduced.
Ques: Why have nails sharp edges?
Ans: Nails have sharp edge because if per unit area of surface is reduced the pressure on it is increased. Hence nails push easily.
Ques: What is atmosphere ?
Ans: Envelop of air is known as the atmosphere.
Ques: What is atmospheric pressure?
Ans: The pressure exerted by this air is known as atmospheric pressure.