Question

Given below are two statements :
Statement (I) : The limiting force of static friction depends on the area of contact and independent of materials.
Statement (II) : The limiting force of kinetic friction is independent of the area of contact and depends on materials.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Statement I is correct but Statement II is incorrect
• B. Statement I is incorrect but Statement II is correct
• C. Both Statement I and Statement II are incorrect
• D. Both Statement I and Statement II are correct

Answer 1

The Correct Option is B

To determine the correct answer, we must evaluate the accuracy of both statements concerning friction:

1. Analysis of Static Friction:
   • Static friction is the force opposing the initiation of sliding between two surfaces.
   • The maximum static friction is determined by the surfaces' properties and the normal force, but it does not vary with the contact area.
   • Consequently, Statement I is erroneous as it inaccurately claims static friction depends on contact area.
2. Analysis of Kinetic Friction:
   • Kinetic friction is the force acting between surfaces in motion relative to each other.
   • The kinetic friction force is independent of the contact area but is dependent on the materials of the surfaces.
   • Therefore, Statement II is accurate because it correctly asserts that kinetic friction is independent of contact area and dependent on material properties.

Determination: Based on the foregoing analysis, the correct conclusion is: Statement I is incorrect, whereas Statement II is correct.