Which of the following is not a non - contact force ?

Options

A. electrostatic force
B. gravitational force
C. frictional force
D. magnetic force

Answer

To determine which of the given forces is not a non-contact force, we will analyze each option provided:

1. **Electrostatic Force**: This is the force between charged objects. It acts at a distance without the objects needing to be in contact. Therefore, it is a non-contact force.

2. **Gravitational Force**: This is the force of attraction between two masses. For example, when an object falls towards the Earth, it is influenced by gravitational force even before it touches the ground. Hence, it is also a non-contact force.

3. **Frictional Force**: This force arises when two surfaces are in contact with each other. It opposes the motion of an object sliding or rolling on a surface. Since frictional force requires contact between the surfaces, it is a contact force.

4. **Magnetic Force**: This is the force exerted by magnets on other magnets or magnetic materials. It can act at a distance, meaning it does not require contact to exert its influence. Thus, it is a non-contact force.

From this analysis, we can conclude that the frictional force is the only force among the options that is not a non-contact force.

### Final Answer:
The force that is not a non-contact force is **Frictional Force**.

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