Which of the following is not a derived force?

Options

A. Tension in a string
B. van der Waal force
C. Nuclear force between proton-proton
D. Electrostatic force between proton-proton

Answer

To determine which of the following is not a derived force, we first need to understand what derived forces are. Derived forces are those that can be calculated using mathematical formulas based on fundamental principles of physics.

### Step-by-Step Solution:

1. **Identify the Forces**:
We need to consider the forces mentioned in the question. The options typically include:
- Tension
- Van der Waals forces
- Nuclear force
- Electrostatic force

2. **Analyze Each Force**:
- **Tension**: This is a force that can be calculated using the principles of mechanics, such as in a rope or string under load. Therefore, tension is a derived force.
- **Van der Waals Forces**: These are intermolecular forces that can be calculated using various models and theories in physics. Thus, they are also considered derived forces.
- **Nuclear Force**: This is the force that holds protons and neutrons together in an atomic nucleus. Currently, there is no direct method to calculate nuclear forces accurately with a formula. They are very strong and complex, making them not a derived force.
- **Electrostatic Force**: This force can be calculated using Coulomb's law, which provides a mathematical formula to determine the force between charged particles. Therefore, it is a derived force.

3. **Conclusion**:
Based on the analysis, the nuclear force is the only force among the options that cannot be calculated using a mathematical formula. Hence, it is not a derived force.

### Final Answer:
The force that is not a derived force is the **Nuclear Force**.

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