Newton's Third Law of Motion governs this scenario. When friction exists between a car's wheel and the ground, the wheel exerts a horizontal force backward on the ground, and by Newton's Third Law, the ground exerts an equal and opposite horizontal force forward on the wheel.

Core Principle Explained

Newton's Third Law states that for every action, there is an equal and opposite reaction. Here, the wheel pushes backward on the ground (action force), so the ground pushes forward on the wheel (reaction force), enabling the car to accelerate.

This static friction prevents slipping during rolling motion without sliding.

Real-World Context

In accelerating cars (like rear-wheel drive), the driven wheels tend to rotate faster, attempting backward motion at the contact point, so friction acts forward on the wheel.

For braking, friction reverses to oppose forward slipping.

Common Misconceptions

  • Direction confusion : The force by the wheel on the ground is backward, not forward—opposite to what propels the car.
  • Static vs. kinetic : Pure rolling uses static friction (no slip); kinetic friction occurs with skidding.

Scenario| Force by Wheel on Ground| Force by Ground on Wheel
---|---|---
Accelerating| Backward| Forward (propels car) 6
Braking| Forward| Backward (slows car) 3
Constant speed (no slip)| Zero horizontal| Zero horizontal 7

TL;DR : Newton's Third Law—action-reaction pair between wheel and ground.

Information gathered from public forums or data available on the internet and portrayed here.