# If an object with uniform acceleration (or deceleration) has a speed of 12 m/s at t=0 and moves a total of 22 m by t=4, what was the object's rate of acceleration?

Dec 16, 2015

$- 3.25 {\text{m/s}}^{2}$

#### Explanation:

Use the equation of motion:

$s = u t + \frac{1}{2} a {t}^{2}$

$\therefore 22 = \left(12 \times 4\right) + \left(0.5 \times a \times {4}^{2}\right)$

$\therefore 22 = 48 + 8 a$

$\therefore a = - \frac{26}{8} = - 3.25 {\text{m/s}}^{2}$