question_answer

Given \[{{m}_{A}}=30kg,\]\[{{m}_{B}}=10kg,\] \[{{m}_{C}}=20kg\] Between A and B \[{{\mu }_{1}}=0.3,\]between B and C \[{{\mu }_{2}}=0.2,\] and between C and ground \[{{\mu }_{3}}=0.1\].   What is the least horizontal force F (in N) to start motion of any part of the system of three blocks resting upon one another as shown in figure \[(g=10m/{{s}^{2}})\]

Answer:

60