Forces - SS1 Physics Past Questions and Answers - page 2

Contact forces are forces that require physical contact between objects for them to be exerted. Examples of contact forces include frictional force, tension force in a rope, and normal force between objects. These forces arise from the direct interaction between the surfaces of objects and can vary depending on factors like the nature of the surfaces and the applied force.

Non-contact forces are forces that can act between objects without any physical contact. These forces can act over a distance through fields or interactions between particles. Examples of non-contact forces include gravitational force, electromagnetic force, and magnetic force. These forces do not require direct physical contact between objects for them to be exerted and can act across empty space.

The main difference between contact and non-contact forces lies in the requirement of physical contact. Contact forces involve direct interaction at the point of contact between objects, while non-contact forces act over a distance without physical touch.

Friction is a contact force that opposes the relative motion or tendency of motion between two surfaces in contact. It arises due to the roughness and interlocking of surface irregularities between objects. Friction plays a significant role in our everyday lives.

Gravitational force is a non-contact force that exists between any two objects with mass. It is an attractive force that acts over a distance, causing objects to be drawn towards each other. The strength of the gravitational force depends on the masses of the objects and the distance between them.

Equilibrium of forces refers to a state in which the net force acting on an object or a system is zero, resulting in a balanced condition. In equilibrium, the object or system experiences no acceleration and remains either at rest or moves with a constant velocity. Examples of objects in equilibrium include a book sitting on a table, a person standing still, or a car moving at a constant speed on a straight road.