In this problem, we are required to calculate the **time** a __decelerating__ object takes come to rest and the** distance covered** before stopping, given its __initial velocity__,** v _{0}** and the

This is a Kinematics problem since it involves **initial velocity**, **v _{0}**,

We'll follow the following simple steps!

- Identify the
**target variable**,**knowns**, and Unknowns for each part of the problem—remember that only**3**of the**5**variables (Δx, v_{0}, v_{f}, a, and t) are needed to solve any kinematics problem. __Choose a UAM equation__with**only one unknown**, which should be our**target variable**.__Solve the equation__for the target variable, then__substitute known values__and__calculate__the answer.

We need to remember the four kinematic equations in order to solve the problem. These are:

$\overline{){{\mathit{v}}}_{{\mathit{f}}}{\mathbf{=}}{{\mathit{v}}}_{{\mathbf{0}}}{\mathbf{+}}{\mathit{a}}{\mathit{t}}\phantom{\rule{0ex}{0ex}}{\mathit{\Delta}}{\mathit{x}}{\mathbf{=}}{\mathbf{\left(}}\frac{{\mathit{v}}_{\mathit{f}}\mathbf{+}{\mathit{v}}_{\mathbf{0}}}{\mathbf{2}}{\mathbf{\right)}}{\mathit{t}}\phantom{\rule{0ex}{0ex}}{\mathit{\Delta}}{\mathit{x}}{\mathbf{=}}{{\mathit{v}}}_{{\mathbf{0}}}{\mathit{t}}{\mathbf{+}}\frac{\mathbf{1}}{\mathbf{2}}{\mathit{a}}{{\mathit{t}}}^{{\mathbf{2}}}\phantom{\rule{0ex}{0ex}}{{{\mathit{v}}}_{{\mathit{f}}}}^{{\mathbf{2}}}{\mathbf{=}}{{{\mathit{v}}}_{{\mathbf{0}}}}^{{\mathbf{2}}}{\mathbf{+}}{\mathbf{2}}{\mathit{a}}{\mathit{\Delta}}{\mathit{x}}}$

On a dry road, a car with good tires may be able to brake with a constant deceleration of 4.92 m/s.

(a) How long does such a car, initially traveling at 24.6 m/s, take to stop?

(b) How far does it travel in this time?

(c) Graph *x * versus *t *and *v* versus *t *for the deceleration.