Question

q

Answer 1

q attached below

Answer 2

find \(\ddot{s}\),
set it equal to \(3\) and solve \(t\)

Answer 3

so we can find the velocity by 1st derivative

\[\fbox{1}...s'(t)=v(t)=-\frac{16}{5} e^{(-0.4t)}-6+2t\]
and we can find acceleration by 2nd derivative\[2......s''(t)=v'(t)=a(t)=\frac{32}{25}e^{(-0.4t)}+2=3\]
solve for t then use it in equation 1