Question

which of the following best describes friction? a force that acts in the direction of motion a force that acts perpendicular to the surface a force that increases the speed of an object a force that opposes the relative motion between two surfaces

Explanation:

Friction is a force that acts to resist the relative motion between two surfaces in contact. It opposes the motion (or tendency of motion) of one surface over the other. For example, when you push a book on a table, friction acts in the opposite direction to your push.

• The first option ("A force that acts in the direction of motion") is incorrect because friction opposes motion, not aids it.
• The second option ("A force that acts perpendicular to the surface") describes the normal force, not friction.
• The third option ("A force that increases the speed of an object") is wrong as friction generally slows down or resists the motion of an object.
• The fourth option ("A force that opposes the relative motion between two surfaces") correctly aligns with the definition of friction.

Answer:

A force that opposes the relative motion between two surfaces