Question

In which situation will the friction between the object and surface on which it is moving be increased. A the object is pushed over a long distance. b the weight of the moving object is decreased. C the object is pushed with greater force against the surface. D the surface on which the object is moving is made smoother

Answer 1

Answer:

C the object is pushed with greater force against the surface

Explanation:

The force of friction between an object and a surface is the resistive force exerted by the surface on the object, due to the roughness of the two surfaces, and that tends to resist the motion of sliding of the object over the surface.

The force of friction exerted on an object over a surface is given by

$F_f=\mu N$

where

$\mu$ is the coefficient of friction, whose value depends on the roughness of the surface

N is the normal reaction exerted by the sutrface on the object

Let's now analyze each statement; here we want the force of friction to be increases:

A the object is pushed over a long distance. --> FALSE, this is independent on the force of friction.

b the weight of the moving object is decreased. --> FALSE: if the weight decreases, the normal reaction decreases, so the force of friction decreases as well.

C the object is pushed with greater force against the surface. --> TRUE: in this case, the normal reaction increases, so the force of friction increases.

D the surface on which the object is moving is made smoother --> FALSE: in this case, the coefficient of friction decreases, so the force of friction decreases.