Review the cause add effects of friction. Describe the effects friction has on moving objects and the need to apply a constant force to keep an object moving. Diagram the affect a rolling mass will have on the height reached when the objet moves down a ramp and then up the other side. Show that as the ramp becomes elongated on the return side, the mass reaches a higher return point. Elicit what would occur if the return ramp was infinite. Determine that the mass would roll indefinitely until stopped gy an external force.