The position function is
.
(a)
\Find velocity
.
.
Apply derivative on each side with respect to
.

.
The velocity is
.
Find acceleration
.
.

.
The acceleration is
.
(b)
\Find the open
-intervals.
Equate
.

and
.
and
.
The open
-intervals are
and
.
(c)
\Find value of
.
Equate
.

.
Find velocity of the particle when the acceleration is zero.
\ Substitute
in
.

.
The velocity of the particle when the acceleration is zero is
.
(a) Velocity:
and acceleration:
.
(b) Open
-intervals :
and
.
(c) The velocity of the particle when the acceleration is zero is
.