The reaction mechanism involves nitration followed by hydrolysis:
\[ \text{Bromobenzene} \xrightarrow{\text{Conc. HNO}_3} \text{Bromonitrobenzene (A)} \]
Then:
\[ \text{Bromonitrobenzene (A)} \xrightarrow{\text{NaOH, HCl}} \text{p-Bromophenol (B)} \]
A body of mass 1000 kg is moving horizontally with a velocity of 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is: