Car physics Braking and Accelerating Why does a car nose up when accelerating and nose down when braking. and when i try to move in reverse with the handbrake on the car rear move up ?
 A: This results from torque, $\boldsymbol{\tau} = \mathbf{r} \times \mathbf{F}$.  In the braking case, the torque is out of the screen because the moment arm, $\mathbf{r}$, is generally downward and the force (i.e., between tire and road), $\mathbf{F}$, is generally directed toward the back of the car (e.g., see example diagram below).  In the acceleration case, the force is directed toward the front of the car and $\mathbf{r}$ is the same.

The direction of torque defines the axis about which the object experiencing the torque will rotate (in a right-handed sense).  So in the braking(accelerating) case, the car will want to rotate in a counterclockwise(clockwise) sense.
A: A car's tail typically rises when attempting to reverse with the handbrake (parking brake) still applied is down to the design of the rear suspension. Cars with a handbrake that acts on the front wheels, such as the Citroen BX, does not display this trait owing to the differing designs of typical front suspension/steering systems when compared to the rear. I will find & post some diagrams to illustrate.
