Friction's role in braking

Steps:

• Braking distance depends on frictional force, which decelerates the car.
• On wet roads, water reduces tire-road contact, lowering the coefficient of friction μ.
• Frictional force F = μN (where N is normal force), so μ decreases, F decreases.
• Braking distance d = v² / (2as), where a = μ g; lower μ means lower a, longer d.

Why C is correct:

• Newton's second law and friction formula show decreased μ on wet roads increases d while decreasing F = μmg.

Why the others are wrong:

• A: Braking distance increases on wet roads, not decreases.
• B: Frictional force decreases on wet roads, not increases.
• D: Frictional force decreases on wet roads, not increases.

Final answer: C