Friction Drive

Friction Drive
Why Physics is more fuel efficient to drive on the road in a city?

In terms of Newton 1 and 2 of the laws motion and static and kinetic friction, why is it more fuel efficient to drive on the road in a city?

Well, the city has to stop and turn several times, which is rarely on the road. Now, when stopping or turning is necessary to apply the brakes fully from the previous and partially (to slow) for the evening. Before applying the brakes the car has a momentum p. When the car slows or stops, there is a change in momentum. Rate change in momentum equals the applied force (Newton's second law) or mathematically: F = Ap / t = Δmv / t [M t-mass and duration of change] So that, as force is required, the more work the more fuel is consumed. The second law can also be written in more familiar form: F = ma [a = 'change speed "/" time "= dV / l] or the more advanced form: F = dp / dt = d (mv) / dt. The first law just tells us the car will continue in movement without "extra" force. Kinetic friction is generally less than static friction, so when the car speed recover after slowing down or stopping of it has to overcome more friction and therefore greater fuel strength therefore more consumed.