Question

Maximum acceleration of the train in which a $50\, kg$ box lying on its floor will remain stationary (Given : Co-efficient of static friction between the box and the train?? floor is $0.3$ and $g = 10 \,ms^{-2}$)

• A. $5.0 \, ms^{-2}$
• B. $3.0 \, ms^{-2}$
• C. $1.5 \, ms^{-2}$
• D. $15 \, ms^{-2}$

Answer 1

Answer: (B)

$3.0 \, ms^{-2}$

Answer 2

Key Idea Motion is possible when $m a \geq \mu m g$. The maximum static frictional force $=\mu_{s} m g$ should be equal to force $F=m a$ $\therefore F=m a=\mu_{s} m g$ $\Rightarrow a=\mu_{s} g$ Here, $\mu_{s}=0.3 . g =10 \,ms ^{-2}$ $a=(0.3) \times 10$ $\Rightarrow a=3\, ms ^{-2}$