A block \(A\) of mass \(7\) kg is placed on a frictionless table. A thread tied to it passes over a frictionless pulley and carries a body \(B\) of mass \(3\) kg at the other end. The acceleration of the system will be: (given \(g=10~\text{m/s}^2)\)

A simple pendulum hangs from the roof of a train moving on horizontal rails. If the string is inclined towards the front of the train, then the train is:

The strings and pulleys shown in the figure are massless. The reading shown by the light spring balance \(S\) is:

In the given figure, the spring balance is massless, so the reading of the spring balance will be: