Question

the city is using sand trucks to place sand on the road during icy conditions. which best explains the use of sand?
the sand increases friction by increasing surface area.
the sand increases friction by increasing roughness.
the sand decreases friction by increasing surface area.
the sand decreases friction by increasing roughness.

Explanation:

Sand is applied to icy roads to improve traction by increasing friction. Icy roads are smooth, so adding sand creates a rougher surface between tires and the road, which boosts friction. The key factor here is increased surface roughness, not surface area, and the goal is to increase (not decrease) friction to prevent slipping.

Answer:

B. The sand increases friction by increasing roughness.