Question

Which of the following is incorrect about the gravitational force between two bodies?

• A. Conservative force
• B. Attractive force
• C. Not a central force
• D. Not a contact force

Hint:

Key properties of the gravitational force: - It is always attractive. - It is a central force (acts along the line connecting the centers of mass). - It is a conservative force (associated with a potential energy). - It is a non-contact, action-at-a-distance force. - It follows an inverse-square law.

Answer 1

The Correct Option is C

Step 1: Analyze each statement about the gravitational force.
(A) Conservative force: A force is conservative if the work done by it in moving a particle between two points is independent of the path taken. The gravitational force is a classic example of a conservative force. The work done depends only on the change in gravitational potential energy. So, this statement is correct.
(B) Attractive force: The gravitational force between any two masses is always attractive; it pulls the objects toward each other. This statement is correct.
(C) Central force: A central force is a force that is always directed towards or away from a single point (a center) and whose magnitude depends only on the distance from that center. The gravitational force between two point masses acts along the line joining them and depends only on the distance between them. Therefore, it is a central force. The statement "Not a central force" is incorrect.
(D) Contact force: Contact forces are forces that act at the point of contact between two objects (like friction, normal force). The gravitational force acts between objects even when they are separated by a large distance (action-at-a-distance). Therefore, it is not a contact force. This statement is correct.

Step 2: Identify the incorrect statement.
Based on the analysis, the only incorrect statement is (C). The gravitational force is a central force.