
The acceleration of the 2 kg block in a system with frictionless surfaces and ideal pulleys and string is determined by analyzing the forces and accelerations. The weight of the 2 kg block is \( 2g \), where \( g \) is the acceleration due to gravity.
Let \( T \) be the tension in the string. For the 2 kg block, Newton's second law yields \( T = 2a \), where \( a \) is its acceleration.
For a block of mass \( M \) on the opposite side, accelerating upwards with tension \( T \), the forces result in \( Mg - T = Ma \).
Given that the acceleration of the 2 kg block is \(\frac{g}{3}\), this is derived by considering the tension relations and force balances within the idealized system.
Conclusion: The acceleration of the 2 kg block is \(\frac{g}{3}\).