Question

Value(s) of m for which the system remains at rest (pulleys and strings are ideal) is/are: $(g=10m/s^2)$

• A. 1 kg
• B. 2 kg
• C. 18 kg
• D. 20 kg

Answer 1

Answer: (B), (C)

18 kg
2 kg

Friction force by block of mass 20 kg, $f=\mu \left(20\right)\left(10\right)=0.4\times 200=80N$
In equilibrium,
for minimum value of m, $mg=10g-80=20,m_{min}=2kg$
for max of m, $mg=10g+80=180,m_{max}=18kg$
So (B) , (C) are the correct option.