irodov again

its a basic question from kinematics which has cinfused me
a particle completes half a circle of radius 160cm in the time interval 10s. Calculate the following quantites averaged over the whole time interval.
the mean veloicty
and the modulus of the mean velocity vector
i hv got really confused in this question

avg of any qunatity is f(x)\int_{0}^{}tf{(x)dt}
so for the mean veocity it will become vdt but for small intervals vdt will become the tota disntance travelled is my logic correct

and pls help me with th e2nd part of the question