# Homework Help: DIfference between a rolling and a spinning wheel

1. Apr 3, 2014

### eterna

1. The problem statement, all variables and given/known data

"Assume you want the car to accelerate towards the right. When a wheel is spinning, the contact point with the ground is moving towards the left. The direction of the frictional force on the portion of the wheel contacting the ground is opposite to the direction of the velocity of this portion of the wheel with respect to the ground. When a wheel is rolling the contact point is not sliding at all. When a rolling wheel is accelerating, internal forces try to accelerate the contact point backward. The force of static friction now is directed towards the right and it cancels those forces. Neglecting drag, the force of static friction is the only external force acting on the car in the horizontal direction, and without it there would be no net force to accelerate the car."

can someone explain the difference between a spinning and a rolling wheel in this case

2. Relevant equations

3. The attempt at a solution

2. Apr 4, 2014

### BvU

Take a toy wheel or something else wheel-shaped and experiment on a smooth surface. Repeat with a sheet of paper between the wheel and the surface.