A car is standing 200 m behind a bus, which is also at rest. The two start moving at the same instant but with different forward accelerations. The bus has acceleration $2 \mathrm {~m} \mathrm {~s} ^ { - 2 }$ and the car has acceleration $4 \mathrm {~m} \mathrm {~s} ^ { - 2 }$. The car will catch up with the bus after time :\\
(1) $\sqrt { 120 } \mathrm {~s}$\\
(2) 15 s\\
(3) $\sqrt { 110 } \mathrm {~s}$\\
(4) $10 \sqrt { 2 } \mathrm {~s}$