Question

A particle starts from rest at time $t=0$ and moves on a straight line with an acceleration which varies with time as shown in fig. The speed of the particle will be maximum after how many seconds?

• A. $4$
• B. $5$
  
• C. $6$
  
• D. $1$
  

Answer 1

The correct option is A $4$

Taking the motion from $0$ to $4$sec

$u=0,a=-10㎨,t=4,v=?$

$v=u+at;v=0-10\times 4$

$\therefore v=-40㎧$

Taking the motion from $2$ to $4$sec

$u=-40,a=10㎧,t=6,v=?$

$v=u+at;v=-40+\left(10\right)\times 6$

$\therefore v=20㎧$

Hence the speed of the particle will be maximum after $4$ sec