A massless spring balance is attached to $2 \mathrm{kg}$ trolley and is used to pull the trolley along a flat surface as shown in the figure. The reading on the spring balance remains at $10 \mathrm{kg}$ during the motion. The acceleration of the trolley is: $\left(g=9.8 \mathrm{m} {\mathrm{s}}^{-2}\right)$

The system shown in the figure is in equilibrium and at rest. The spring and string are massless. Now the string is cut. The acceleration of mass $2m$ and $m$ just after the string is cut will respectively be:

Two blocks $A$ and $B$ of masses $m$ and $2 m$ respectively, are held at rest such that the spring is in natural length. What is the acceleration of both the blocks just after the release?

A man weighs $80 \mathrm{kg}$. He stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of $5 \mathrm{m} {\mathrm{s}}^{-2}$. What would be the reading on the scale? $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$