Which of the following examples illustrates static friction? a box sits stationary on a ramp, a ball rolling on a lawn eventually comes to a rest, a car rounds a curve on the road, a fish swims upstream.

Option (a) is the correct answer.

Explanation:

Static friction is defined as the friction that occurs between a stationary object and the surface on which it is resting.

For example, a box resting on a ramp is stationary and a static friction occurs between the box and the ramp.

Whereas when an object moves from one place to another then there exists kinetic friction between the moving object and the surface on which it moves.

Therefore, we can conclude that out of the given examples, a box sits stationary on a ramp illustrates static friction.

b is the best answer for this question.