Static Friction Video Lessons

Concept

# Problem: Q1: When two objects slide against one another, which of the following statements about the force of friction between them is true?a. The magnitude of the frictional force is always equal to μkN .b. The magnitude of the frictional force is always less than μkN .c. The magnitude of the frictional force is determined by other forces on the objects so it can be either equal to or less than μkN .Q2: When two objects are in contact with no relative motion, which of the following statements about the frictional force between them is true?a. The magnitude of the frictional force is always equal to μsNb. The magnitude of the frictional force is always less than μsNc. The magnitude of the frictional force may be either equal to or less than μsN.

###### FREE Expert Solution

Q1:

Kinetic friction:

$\overline{){{\mathbf{f}}}_{{\mathbf{k}}}{\mathbf{=}}{{\mathbf{\mu }}}_{{\mathbf{k}}}{\mathbf{N}}}$

When two objects are in motion, static friction opposes the motion of the objects.

###### Problem Details

Q1: When two objects slide against one another, which of the following statements about the force of friction between them is true?

a. The magnitude of the frictional force is always equal to μkN .

b. The magnitude of the frictional force is always less than μkN .

c. The magnitude of the frictional force is determined by other forces on the objects so it can be either equal to or less than μkN .

Q2: When two objects are in contact with no relative motion, which of the following statements about the frictional force between them is true?

a. The magnitude of the frictional force is always equal to μsN

b. The magnitude of the frictional force is always less than μsN

c. The magnitude of the frictional force may be either equal to or less than μsN.