A bird is sitting on the floor of a wire cage and the cage is in the hand of a boy . The bird starts flying in the cage . Will the boy experience any change in the weight of the cage ?

Options

A. Unchanged
B. Reduced
C. Increased
D. Nothing can be said

Explanation

To determine whether the boy experiences any change in the weight of the cage when the bird starts flying inside it, we can analyze the forces acting on the system step by step.

### Step-by-Step Solution:

1. **Initial Situation**:
- The bird is sitting on the floor of the cage.
- The total weight that the boy feels in his hand is the sum of the weight of the cage (W_cage) and the weight of the bird (W_bird).
- Therefore, the total force (weight) experienced by the boy is:
\[ F_{total, initial} = W_{cage} + W_{bird} \]

2. **Bird Starts Flying**:
- When the bird starts to fly, it exerts a downward force equal to its weight (W_bird) on the air inside the cage.
- According to Newton's third law, for every action, there is an equal and opposite reaction. Therefore, the air pushes back with an equal force upward.

3. **Force Exerted by the Bird**:
- To maintain flight, the bird must exert a force equal to its weight downward onto the air. This force is transmitted through the air to the base of the cage.
- Thus, the air exerts an upward force on the cage equal to the weight of the bird.

4. **Total Force on the Cage While Bird is Flying**:
- The total force on the cage now consists of the weight of the cage and the upward force exerted by the air (which is equal to the weight of the bird).
- Therefore, the total force (weight) experienced by the boy when the bird is flying is:
\[ F_{total, flying} = W_{cage} + W_{air} = W_{cage} + W_{bird} \]

5. **Comparison of Forces**:
- We can see that:
\[ F_{total, initial} = F_{total, flying} \]
- This means that the total weight experienced by the boy does not change when the bird starts flying.

### Conclusion:
The boy will not experience any change in the weight of the cage when the bird starts flying inside it. The forces balance out, and the total weight remains constant.