When an object is at rest -

Options

A. Force is required to keep it in rest state
B. No force is acting on it
C. A large number of forces may be acting on it which balance each other
D. A large number of forces may be acting on it which not balance each other

Answer

### Step-by-Step Solution:

1. **Understanding the Problem**: We need to analyze the situation when an object is at rest. An object at rest means that it is not moving and is in a state of equilibrium.

2. **Identifying Forces**: Let's denote the mass of the object as \( m \). Assume there are multiple external forces acting on this object, which we will call \( F_1, F_2, F_3, F_4, \) and \( F_5 \).

3. **Vector Summation of Forces**: The total external force acting on the object can be expressed as the vector sum of all these forces:
\[ F_{\text{total}} = F_1 + F_2 + F_3 + F_4 + F_5 \]

4. **Condition for Equilibrium**: For the object to be at rest (in equilibrium), the net external force must be zero:
\[ F_{\text{total}} = 0 \]
This means that the vector sum of all the forces acting on the object must cancel each other out.

5. **Example Scenario**: Consider a block of mass \( m \) resting on a smooth horizontal surface. The forces acting on it include:
- The gravitational force acting downwards, \( mg \) (weight of the block).
- The normal force \( N \) acting upwards from the surface.

6. **Balancing Forces**: In this scenario, the downward force (weight) is balanced by the upward normal force:
\[ N = mg \]
Here, both forces are non-zero, but they are equal in magnitude and opposite in direction, resulting in a net force of zero.

7. **Conclusion**: Since the net force acting on the object is zero, we conclude that the object is in equilibrium and remains at rest. Therefore, the correct answer to the question is that the forces acting on the object balance each other.