question_answer

A particle of mass \[m\] moves on the x-axis as follows : it starts from rest at \[t=0\] from the point \[x=0\] and comes to rest at \[=(u+at)t+\frac{1}{2}a{{t}^{2}}\] at the point \[x=1\]. No other information is available about its motion at intermediate time \[(0<t<1)\]. If \[\alpha \] denotes the instantaneous acceleration of the particle, then                            [IIT-JEE 1993]

A)             \[\alpha \] cannot remain positive for all \[t\] in the interval \[0\le t\le 1\]

B)             \[|\alpha |\] cannot exceed 2 at any point in its path

C)             \[|\alpha |\] must be \[\ge 4\] at some point or points in its path

D) \[\alpha \] must change sign during the motion but no other assertion can be made with the information given