(a).
\The maximum displacement of the board function when
is
.
Here
is the damping constant of the board.
is the frequency.
is the time.
The maximum displacement constant is
.
The damping constant of the board
.
the board has moved down
times in
seconds.Theefore in one second it has moved
times.
The frequency
.
And
.
Substitue all the above values into
.

(b).
\Find the amount of time when
.
Graph:
\Graph of
is :

Observe the graph:
\At time
, when
.
Hence
,
(a).
.
(b).
,