# If an object with uniform acceleration (or deceleration) has a speed of 3 m/s at t=0 and moves a total of 80 m by t=4, what was the object's rate of acceleration?

Oct 1, 2017

Using the kinematic formula $D = {v}_{i} \cdot t + \frac{1}{2} a {t}^{2}$,
$D = 80 m$
$t = 4 s$
${v}_{i} = 3 \frac{m}{s}$
a=?

80m = 3m/cancels*4cancels+ 1/2 color(blue)(a) *4^2s
80m-12m=8*color(blue)(a
72m=8*color(blue)(a
$a = \frac{72}{8} = 9 \frac{m}{s} ^ 2$