Stitching patterns on the straight edge of a head gear is done by a sewing machine. The initial velocity of the sewing machine is [math]20cms^{-1}[/math]. Its acceleration, in [math]cms^{-2}[/math] , is given by [math]a=8-2t[/math], where t is the time, in seconds, after passing through a fold.
(a) the instantaneous velocity of the sewing, in [math]cm^{-1}[/math], at the 2nd second.
(b) the instantaneous velocity of the sewing in [math]cm^{-1}[/math] , when the acceleration is 0.
(c) the time, in seconds, of the sewing when the acceleration is [math]5cms^{-2}[/math],
(d) the value of t, in seconds, when the velocity of the sewing is [math]11cms^{-1}[/math]