As far as mechanics is concerned all systems of units are having the same dimensions for a given physical quantity. But for thermodynamics, electricity, magnetism and electromagnetics this is not the case. Why?

Explanation

To understand why all systems of units have the same dimensions for a given physical quantity in mechanics but not in thermodynamics, electricity, magnetism, and electromagnetism, we can break down the explanation into a few key steps.

### Step-by-Step Solution:

1. **Understanding Dimensions in Mechanics**:
- In mechanics, the fundamental physical quantities are length, mass, and time. These quantities are universally accepted and have the same dimensions across different unit systems (e.g., SI, CGS).
- For example, the dimension of force is [M L T^-2], which remains consistent regardless of the unit system used.

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