Two trains are moving on the same track in opposite directions with velocities and

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

Two trains are moving on the same track in opposite directions with velocities

v_1=10\text{ m s}^{-1}

and

v_2=20\text{ m s}^{-1}

. After brakes are applied, their retarding rates are

a_1=2\text{ m s}^{-2}

and

a_2=1\text{ m s}^{-2}

, respectively. The minimum separation required to avoid collision is (1)

150\text{ m}

(2)

225\text{ m}

(3)

450\text{ m}

(4)

300\text{ m}