# If an object with uniform acceleration (or deceleration) has a speed of 4 m/s at t=2 and moves a total of 25 m by t=6, what was the object's rate of acceleration?

Apr 23, 2018

The acceleration is $= 1.125 m {s}^{-} 2$

#### Explanation:

The initial speed is $u = 4 m {s}^{-} 1$

The distace is $s = 25 m$

The time is $\Delta t = 6 - 2 = 4 s$

Apply the equation of motion

$s = u \Delta t + \frac{1}{2} a {\left(\Delta t\right)}^{2}$

The acceleration is

$a = \frac{s - u \Delta t}{\frac{1}{2} {\left(\Delta t\right)}^{2}}$

$= \frac{25 - 4 \times 4}{\frac{1}{2} \times {4}^{2}}$

$= \frac{9}{8}$

$= 1.125 m {s}^{-}$