Answer
$\sqrt{293}$
Work Step by Step
Recall: The speed of the particle is formulated by $v(t)=\sqrt{(dx/dt)^2+(dy/dt)^2}$.
Find $dx/dt$ and $dy/dt$:
$dx/dt=2$ and $dy/dt=4t-3$
Evaluate $v(t)$ at $t=5$:
$v(t)=\sqrt{2^2+(4t-3)^2}$
$v(5)=\sqrt{2^2+(4\cdot 5-3)^2}$
$v(5)=\sqrt{4+17^2}$
$v(5)=\sqrt{293}$
Thus, the speed of the particle at time $t=5$ is $\sqrt{293}$.