Discussion Forum

1)

Two masses m₁= 5 kg and m_{2 =} 10 kg connected by an inextensible string over a frictionless pulley , are moving as shown in the figure. The coefficient of friction of horizontal surface is 0.15. The minimum weight  m that should be put on top of m₂ to stop the motion is

Answer:

Option D

Explanation:

Motion stops when pull due to m₁≤ force of friction between m and m₂ and surface.

$\Rightarrow   m_{1}g\leq\mu(m_{2}+m)g$

$\Rightarrow    5\times10\leq0.15(10+m)\times10$

$\Rightarrow m\geq23.33kg$

Here, nearest value is 27.3 kg

So,  $m_{min}=27.3kg$