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We are given:

- A uniform disc with:
  - Radius \( r = 20 \, \text{cm} = 0.2 \, \text{m} \)
  - Mass \( m = 2 \, \text{kg} \)
- A force \( F = 2 \, \text{N} \) applied via a massless cord wound along the rim.
- We need to find the **tangential acceleration** of a point on the rim of the disc.

### Approach:

1. **Moment of Inertia of the Disc**:  
   The moment of inertia \( I \) for a uniform disc rotating about its center (perpendicular axis) is given by:
   \[
   I = \frac{1}{2} m r^2
   \]
   Substituting the values:
   \[
   I = \frac{1}{2} \times 2 \, \text{kg} \times (0.2 \, \text{m})^2 = 0.04 \, \text{kg} \cdot \text{m}^2
   \]

2. **Torque**:  
   The torque \( \tau \) applied by the force is:
   \[
   \tau = F \times r
   \]
   Substituting the values:
   \[
   \tau = 2 \, \text{N} \times 0.2 \, \text{m} = 0.4 \, \text{N} \cdot \text{m}
   \]

3. **Angular Acceleration**:  
   The angular acceleration \( \alpha \) is related to torque and moment of inertia:
   \[
   \alpha = \frac{\tau}{I}
   \]
   Substituting the values:
   \[
   \alpha = \frac{0.4 \, \text{N} \cdot \text{m}}{0.04 \, \text{kg} \cdot \text{m}^2} = 10 \, \text{rad/s}^2
   \]

4. **Tangential Acceleration**:  
   The tangential acceleration \( a_t \) at the rim is related to the angular acceleration:
   \[
   a_t = \alpha \times r
   \]
   Substituting the values:
   \[
   a_t = 10 \, \text{rad/s}^2 \times 0.2 \, \text{m} = 2 \, \text{m/s}^2
   \]

Thus, the **tangential acceleration** of a point on the rim of the disc is **2 m/s²**.

### Answer:  
The correct option is **(B) 2 m/s²**.

---

Do you want more details or have any questions?

Here are 5 related questions for further understanding:

1. How does the moment of inertia affect angular acceleration in a rotating object?
2. What would happen to the tangential acceleration if the radius of the disc were doubled?
3. How is torque related to angular acceleration in rotational motion?
4. Can the tangential acceleration change if the force is applied closer to the center of the disc?
5. What is the difference between angular and tangential acceleration?

**Tip**: Remember that tangential acceleration depends on both angular acceleration and the distance from the axis of rotation (radius).

A uniform disc of radius 20 cm and mass 2 kg can rotate about a fixed axis through the center perpendicular to its plane. A massless cord is round along the rim of the disc. If a uniform force of 2 newtons is applied on the cord, the tangential acceleration of a point on the rim of the disc will be:

Solve a problem involving a uniform disc with a radius of 20 cm and mass of 2 kg, where a 2 N force is applied via a cord to find the tangential acceleration. This problem explores concepts like moment of inertia, torque, and angular acceleration, suitable for high school students in grades 11-12.

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