The problem describes a normal reaction force acting on an object and asks which of the given statements are true. a) It always acts vertically. b) It always passes through the center of gravity. c) It is the force acting perpendicular to the surfaces of two solid objects in contact at their point of contact. We need to determine which of the statements a, b, and c are true.
2025/6/26
1. Problem Description
The problem describes a normal reaction force acting on an object and asks which of the given statements are true.
a) It always acts vertically.
b) It always passes through the center of gravity.
c) It is the force acting perpendicular to the surfaces of two solid objects in contact at their point of contact.
We need to determine which of the statements a, b, and c are true.
2. Solution Steps
Statement a: The normal reaction force does not always act vertically. It acts perpendicular to the surface of contact. If the surface is horizontal, then it acts vertically. But if the surface is inclined, it acts perpendicular to the inclined surface, which is not vertical. So, statement a is false.
Statement b: The normal reaction force does not always pass through the center of gravity. The location of the normal force depends on the distribution of the force over the area of contact. Thus, statement b is false.
Statement c: The normal reaction force is defined as the force acting perpendicular to the surfaces of two solid objects in contact at their point(s) of contact. So, statement c is true.
Thus, only statement c is true.
3. Final Answer
(3) c පමණි