Which of the following class of force is different from others?

Options

A. Magnetic force
B. Electricial force
C. Gravitational force
D. Stretching of a spring

Answer

To determine which class of force is different from the others among the given options (magnetic force, electrical force, gravitational force, and stretching of a spring), we can analyze each option based on whether they are contact forces or non-contact forces.

### Step-by-Step Solution:

1. **Identify the Types of Forces**:
- **Magnetic Force**: This is a non-contact force that acts at a distance. It can affect charged particles without any physical contact.
- **Electrical Force**: This is also a non-contact force. It acts between charged objects without requiring them to be in contact.
- **Gravitational Force**: This is another non-contact force. It acts between two masses regardless of their physical contact.
- **Stretching of a Spring**: This is a contact force. To stretch a spring, you must physically pull it, which requires contact with the spring.

2. **Classify Each Force**:
- Magnetic Force: Non-contact
- Electrical Force: Non-contact
- Gravitational Force: Non-contact
- Stretching of a Spring: Contact

3. **Compare the Forces**:
- The first three forces (magnetic, electrical, and gravitational) are all non-contact forces. They can exert influence over a distance without any physical interaction.
- The stretching of a spring, however, requires direct contact to exert force and create an extension.

4. **Conclusion**:
- The force that is different from the others is the **stretching of a spring** because it is a contact force, while the others are non-contact forces.

### Final Answer:
The stretching of a spring is the force that is different from the others.

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