JEE Advanced 2020 Concept Recapitulation Test 2 Paper 1

Three blocks a, b, and c of masses 10kg,10kg and 20kg are arranged as shown in figure. All the surfaces are frictionless and string is inextensible. Pulleys are light. A constant force F=20N is applied on block a as shown. Pulleys and string are light. Part of the string connecting both pulleys is vertical and part of the strings connecting pulleys with blocks a and b are horizontal.