A bird is sitting in a large closed cage which is placed on a spring balance. It records a weight of 25 N. The bird (mass=0.5 kg) flies upward in the cage with an acceleration of `2m//s^(2)`. The spring balance will now record a weight of :-

Options

A. 24 N
B. 25 N
C. 26 N
D. 27 N

Answer

To solve the problem, we need to analyze the forces acting on the bird when it flies upward in the cage.

### Step-by-Step Solution:

1. **Identify the Weight of the Bird**:
The spring balance initially records a weight of 25 N. This weight includes the weight of the bird and the cage.
\[ W = mg \]
where \( W \) is the weight, \( m \) is the mass, and \( g \) is the acceleration due to gravity (approximately \( 9.8 \, \text{m/s}^2 \)).

2. **Calculate the Mass of the Bird**:
Given that the mass of the bird is \( 0.5 \, \text{kg} \), we can calculate its weight:
\[ W_{\text{bird}} = m_{\text{bird}} \cdot g = 0.5 \, \text{kg} \cdot 9.8 \, \text{m/s}^2 = 4.9 \, \text{N} \]

3. **Determine the Force Required for the Bird to Fly Upward**:
The bird is flying upward with an acceleration of \( 2 \, \text{m/s}^2 \). The net force required for this upward acceleration can be calculated using Newton's second law:
\[ F = m \cdot a = 0.5 \, \text{kg} \cdot 2 \, \text{m/s}^2 = 1 \, \text{N} \]

4. **Calculate the Pseudo Force**:
When the bird flies upward, it exerts a pseudo force on the spring balance due to its upward acceleration. This pseudo force acts downward and is equal to the force calculated in the previous step:
\[ F_{\text{pseudo}} = 1 \, \text{N} \]

5. **Calculate the New Reading on the Spring Balance**:
The new reading on the spring balance will be the original weight plus the pseudo force exerted by the bird:
\[ W_{\text{new}} = W_{\text{initial}} + F_{\text{pseudo}} = 25 \, \text{N} + 1 \, \text{N} = 26 \, \text{N} \]

### Final Answer:
The spring balance will now record a weight of **26 N**.

---