Frictional force can't be measured in

Options

A. kg wt
B. newton
C. dyne
D. `kgms^(-1)`

Answer

To solve the question "Frictional force can't be measured in", we need to analyze the options provided and determine which one does not represent a unit of force.

### Step-by-Step Solution:

1. **Understanding Frictional Force**:
- Frictional force is a force that opposes the relative motion of two surfaces in contact. The formula for frictional force (F_friction) is given by:
\[ F_{\text{friction}} = \mu \cdot N \]
where \( \mu \) is the coefficient of friction and \( N \) is the normal force.

2. **Identifying Units of Force**:
- The SI unit of force is the Newton (N).
- In the CGS (Centimeter-Gram-Second) system, the unit of force is the dyne.
- Weight can also be expressed in terms of force, specifically in kg-weight (where weight = mass × gravitational acceleration).

3. **Analyzing the Options**:
- **Option 1: kg weight**: This is a unit of force (specifically, the weight of a mass in a gravitational field).
- **Option 2: Newton**: This is the standard SI unit of force.
- **Option 3: dyne**: This is a unit of force in the CGS system.
- **Option 4: kg meter per second**: This expression does not represent a unit of force. Instead, it resembles a unit of momentum (mass × velocity).

4. **Conclusion**:
- Since frictional force is a type of force, it can be measured in kg weight, Newton, or dyne. However, it cannot be measured in kg meter per second, as this is not a unit of force but rather a unit of momentum.

### Final Answer:
Frictional force can't be measured in **kg meter per second** (Option 4).

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