Question map
Which one of the following is not a contact force ?
Explanation
Forces are categorized into contact and non-contact forces based on whether physical interaction is required between objects [2]. A contact force, such as a push force or frictional force, occurs when objects are physically touching [4]. Friction specifically arises due to irregularities between two surfaces in contact [4]. Strain force is also a contact-based interaction resulting from electromagnetic interactions and the Pauli exclusion principle within matter. In contrast, non-contact forces act even when objects are separated by a distance [3]. Gravitational force is a primary example of a non-contact force because the Earth attracts objects towards itself without requiring physical contact [5]. Other examples of non-contact forces include magnetic and electrostatic forces [5]. Therefore, gravitational force is the only option listed that is not a contact force.
Sources
- [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Snapshots > p. 77
- [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > 5.4.1 Contact forces > p. 66
- [4] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.3: Let us investigate > p. 68
- [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > 5.4.2 Non-contact forces > p. 69
- [5] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.8: Let us observe > p. 72