Three masses $\mathrm{m}$, $2\mathrm{m}$ and $3\mathrm{m}$ are moving in $\mathrm{x}$-$\mathrm{y}$ plane with speed $3\mathrm{u}$, $2\mathrm{u}$ and $\mathrm{u}$ respectively as shown in figure. The three masses collide at the same point at P and stick together. The velocity of resulting mass will be: (1) $\frac{u}{12}(\hat{i}+\sqrt{3}\hat{j})$ (2) $\frac{u}{12}(\hat{i}-\sqrt{3}\hat{j})$ (3) $\frac{u}{12}(-\hat{i}+\sqrt{3}\hat{j})$ (4) $\frac{u}{12}(-\hat{i}-\sqrt{3}\hat{j})$
A man of 60 kg is running on the road and suddenly jumps into a stationary trolly car of mass 120 kg. Then the trolly car starts moving with velocity $2\mathrm{~m\,s^{-1}}$. The velocity of the running man was $\_\_\_\_$ $\mathrm{m\,s^{-1}}$, when he jumps into the car.