A block is sliding on a horizontal surface. The friction can be increased by_________________.

Select one:

a.?Decreasing the mass of the block

b.?Decreasing the area of contact with the surface

c.?Polishing the surface

d.?Putting second block on the top

Dear Student

Correct option is (d)

Friction is directly proportional to the weight of the body,  more is the weight of the body more is the frictional force.
Polishing the surface, decreases the friction.
Decreasing the mass of the block decreases the friction.
Friction does not depend on the surface area of an object.

Regards