a
\(\begin{array}{l}
The\,acceleration\,of\,a\,body\,in\,a\,nonunifrom\\
cicular\,motion\,is\,the\,{\rm{resultant}}\,of\,the\,radial\\
and\,the\,t{\rm{angential}}\,{\rm{accelerations}}{\rm{.}}\\
{\rm{If}}\\
{{\rm{a}}_r} = 3m{s^{ - 2}}and\,{a_t} = 4m{s^{ - 2}}\\
then,\,a = \sqrt {{a_r}^2 + {a_t}{\,^2}}  = \sqrt {{{\left( 3 \right)}^2} + {{\left( 4 \right)}^2}} \\
\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \sqrt {9 + 16}  = \sqrt {25}  = 5m{s^{ - 2}}
\end{array}\)