Question 657268
When an object's velocity changes, it {{{accelerates}}}. Acceleration {{{a}}} shows the {{{change}}} in {{{velocity}}} in a {{{unit}}}{{{ time}}}. 

Velocity is measured in meters per second, {{{mil/h}}},{{{ft/s}}} in your case; so, acceleration is measured in {{{(mil/h)/h}}}, or {{{mil/h^2}}} {{{ft/s^2}}} in your case, which can be both positive and negative.

{{{a=(v[1]-v[0])/(t[1]-t[2])}}}

a car that {{{accelerates}}} from {{{rest}}} (means {{{v[0]=0}}} at {{{v[1]=9.0ft/s}}} for {{{t[0]=0}}} and{{{t[1]=8.0s}}}

{{{a=(v[1]-v[0])/(t[1]-t[2])}}}


{{{a=(v[1]-0)/(t[1]-0)}}}


{{{a=v[1]/t[1]}}}


{{{a=9.0(ft/s)/8.0s}}}


{{{a=(9.0/8.0)(ft/s^2)}}}


{{{a=1.125(ft/s^2)}}}