Train A is moving along two parallel rail tracks towards north with speed 72 km/h and train B is moving towards south with speed 108 km/h. Velocity of train B with respect to A and velocity of ground with respect to B are (in m s⁻¹):
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Question

Train A is moving along two parallel rail tracks towards north with speed 72 km/h and train B is moving towards south with speed 108 km/h. Velocity of train B with respect to A and velocity of ground with respect to B are (in m s⁻¹):

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G1 Physics · Accepted Answer

Take north as positive. Velocity of train A: v(A) = +72 km/h = +20 m/s Velocity of train B: v(B) = -108 km/h = -30 m/s Velocity of B relative to A: v(B/A) = v(B) - v(A) = -30 - 20 = -50 m/s Velocity of ground relative to B: v(G/B) = 0 - (-30) = +30 m/s