Identify the correct statement.a)Static friction depends on the area o...
- Both static and kinetic friction are independent on the area of contact.
- Coefficient of static friction depends on the surfaces in contact. μk < μs
Identify the correct statement.a)Static friction depends on the area o...
Explanation:
Friction is the force that opposes the relative motion or tendency of motion between two surfaces in contact. It can be classified into two types: static friction and kinetic friction.
Static Friction:
Static friction is the force that prevents an object from moving when a force is applied to it. It acts in the opposite direction to the applied force, and its magnitude depends on the force applied and the coefficient of static friction between the surfaces in contact. The coefficient of static friction is a dimensionless quantity that represents the roughness or smoothness of the surfaces in contact. It can vary depending on the nature of the surfaces.
Kinetic Friction:
Kinetic friction is the force that opposes the motion of an object when it is already in motion. Unlike static friction, kinetic friction remains constant once the object is in motion. The magnitude of kinetic friction depends on the coefficient of kinetic friction between the surfaces in contact.
Comparison:
Now let's compare the given statements and identify the correct one:
a) Static friction depends on the area of contact.
This statement is incorrect. The magnitude of static friction depends on the force applied and the coefficient of static friction, not the area of contact.
b) Kinetic friction depends on the area of contact.
This statement is also incorrect. The magnitude of kinetic friction depends on the coefficient of kinetic friction, not the area of contact.
c) Coefficient of static friction does not depend on the surfaces in contact.
This statement is incorrect. The coefficient of static friction can vary depending on the nature of the surfaces in contact. Different materials have different coefficients of static friction.
d) Coefficient of kinetic friction is less than the coefficient of static friction.
This statement is correct. In general, the coefficient of kinetic friction is less than the coefficient of static friction. It is easier to keep an object in motion (kinetic friction) than to set it in motion (static friction). The coefficient of kinetic friction represents the resistance to motion between surfaces that are already in relative motion.
Therefore, option 'D' is the correct statement.