Question

The coefficient of static friction between the box and the train’s floor is $0.2$. The maximum acceleration of the train in which a box lying on its floor will remain stationary is
(Take$\, g =10\,m\,s^{-2}$)

• A. $2 \,m$ $s^{-2}$
• B. $4 \,m$ $s^{-2}$
• C. $6 \,m$ $s^{-2}$
• D. $8\, m$ $s^{-2}$

Answer 1

Answer: (A)

As acceleration of the box is due to static friction,
$\therefore \quad$ $ma=f_{s} \le \mu_{s} N=\mu_{s} mg$ $a\le \mu_{s} g$
$\therefore \quad$ $a_{max}$ $=\mu_{s} g$ $=0.2\times10 m$ $s^{-2}$ $=2\, m$ $s^{-2}$