Why does a book on a table not move?

Options

A. No forces are acting on the book
B. Gravity is the only force acting on the book
C. Forces of the table pushing up and gravity pulling down are balanced
D. None of them

Answer

To understand why a book on a table does not move, we can break down the explanation into several steps:

### Step 1: Identify the Forces Acting on the Book
When a book is placed on a table, two main forces act on it:
1. **Gravitational Force (Weight)**: This force pulls the book downward towards the Earth.
2. **Normal Force**: This is the upward force exerted by the table on the book. It acts perpendicular to the surface of the table.

### Step 2: Understand the Nature of Forces
For an object to remain stationary, the forces acting on it must be balanced. This means that the total force acting in one direction must equal the total force acting in the opposite direction.

### Step 3: Analyze the Forces
In the case of the book:
- The gravitational force pulls the book downwards.
- The normal force from the table pushes the book upwards.

### Step 4: Determine if the Forces are Balanced
Since the gravitational force and the normal force are equal in magnitude and opposite in direction, they balance each other out. This can be expressed mathematically as:
\[ \text{Normal Force} = \text{Weight of the Book} \]

### Step 5: Conclusion
Because the forces are balanced, the book does not move. It remains stationary on the table.

### Summary
The book on the table does not move because the downward gravitational force is balanced by the upward normal force from the table, resulting in no net force acting on the book.

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