Can a body have constant speed and still be accelerating?

Is it possible that an object is in a state of accelerated motion due to an external force acting on it,but no work is being done by the force? Explain with an example.

$A$ body is moving along a circular path of radius $R$. Find the displacement of the body when it completes half a revolution.

Give an expression for the speed of an athlete if he takes time $t$ to complete one round of a circular track of radius $r$.

An athlete completes one round of a circular track of diameter $49 \,m$ in $20 \,s$. Calculate the distance covered and displacement at the end of $30 \,s$.

$A$ satellite while revolving around the earth completes one revolution in $1$ hour and $30$ minutes. What is the angular speed of the satellite?