A particle starts from rest at time t=0 and moves on a straight line with acceleration as plotted in fig. The speed of the particle will be maximum after time (in s) $\_\_\_\_\_\_$

Taking the motion from 0 to 2 sec

u = 0,a = −10 m/s², t = 4, v = ?

v = u + at; v = 0 − 10×4

∴v = −40 m/s

Taking the motion from 2 to 4sec
 

u = −40, a = 10㎧, t = 6 , v = ?

v = u + at; v= −40 + (10)×6

∴v = 20 m/s

Hence the speed of the particle will be maximum after 2 sec