Question

20. A block of mass M is placed on a flat surface. A force is applied to move it
parallel to the surface. The frictional force f developed is proportional to the
(A) square of the mass of the body
(b) mass of the body
(c) reciprocal of the mass of the body
(d) reciprocal of the square of the body​

Answer 1

option b

mass of the body

Answer 2

The frictional force is directly proportional to the mass of the body.

Explanation:

• The frictional force is a contact force that resists sliding between the surfaces.

• It is denoted as f.
• The frictional force is given by the formula,
• F = μ×N; where μ is the coefficient of friction and N is the normal force.
• The normal force is defined as the support force exerted upon an object that is in contact with another stable object or surface.
• The normal force can be simply described by the following formula:
• N = mg; where m is the mass of the object and g is the acceleration due to gravity.
• ∴ F = μ×mg
• ⇒ F ∝ m