Question

In cold weather, we rub our hands to warm them. The force involved in this force is:
(A) Static force
(B) Gravitational force
(C) Friction force
(D) Electrostatic force

Answer 1

Hint: To give the answer of this problem we must know about concepts of the Static force, Gravitational force, Friction force, and Electrostatic force without knowing about these forces we cannot answer the question.

Complete step by step answer:
Static Force: A constant force applied to a stationary object is known as static force. This force is very weak to move an object from rest because it is countered by equally strong opposite forces. The most common example of a static force is static friction on a stationary object.
Gravitational force: The force that attracts the object with mass is called gravitational force. This force is always of attractive nature because it always attracts the object. For example gravitational force of earth always attracts the object going away from the earth surface.
Electrostatic force: The force which is acting between the electrically charged particles is known as Electrostatic force. It can be both attractive and repulsive.
Friction force: Friction force is the force acting on a moving object which is equal and opposite to the direction of motion. The cause of friction is irregularities present on the two surfaces. This frictional force is responsible for wearing out tyres of vehicle. This frictional force is not same for every object it varies object to object. It is depend upon the nature of objects. The lubricants are used to reduce the friction in machines. The rough surface produces more friction than smooth surface.
The frictional forces are mainly of four types; Static Friction, Sliding Friction, Rolling Friction, and Fluid Friction.
When we rub our hands, heat is produced due to friction. The force involved in this process is frictional force.

Therefore, the option (C) is the correct answer.

Note:The frictional force is the force which is responsible for resistance in motion on a rough surface. When two bodies are in contact and are in motion then only frictional force will act between them.