Forces between Bodies in Contact

When two bodies are in contact with each other, they experience forces. These forces can be categorized into three types, depending on the nature of the contact:

1. Normal Force:
The normal force is the force exerted by a surface to support the weight of an object resting on it. It acts perpendicular to the surface and prevents the object from sinking into the surface. The normal force is always directed away from the surface, in the opposite direction of the force exerted by the object on the surface.

2. Frictional Force:
The frictional force is the force that opposes the motion or attempted motion of two objects in contact with each other. It acts parallel to the surface of contact and can be further divided into two types: static friction and kinetic friction. Static friction acts to prevent relative motion between the objects, while kinetic friction acts when the objects are already in motion.

3. Tension Force:
The tension force is the force transmitted through a string, rope, cable, or any other type of flexible connector. It acts along the length of the connector and is always directed away from the object to which it is attached.

Direction of Forces:

When two bodies are in contact, the forces they experience can have different directions. The correct answer to the given question is option 'B' - opposite direction. This means that the forces between the bodies in contact act in opposite directions.

For example, consider a book resting on a table. The book exerts a downward force due to its weight, which is balanced by an equal and opposite normal force exerted by the table. These two forces are in contact and act in opposite directions.

Similarly, when a person pushes a box across the floor, the person exerts a forward force on the box, and the box exerts an equal and opposite backward force on the person. Again, these forces are in contact and act in opposite directions.

In conclusion, when two bodies are in contact, the forces they experience are in opposite directions. This is because the forces are action-reaction pairs, following Newton's third law of motion.