Question 988127
Yes, you do need to differentiate.
Velocity is the first derivative of displacement with respect to time and acceleration is the second derivative.
{{{v=dx/dt=-12t^2+16t+1}}}
{{{a=dv/dt=-24t+16}}}
When {{{t=3}}},
{{{v(3)= -12(3)^2+16(3)+1 =-108+48+1=-59}}}{{{m/s}}}
{{{a(3)= -24(3)+16=-72+16=-56}}}{{{m/s^2}}}