Question

Three ships A. B & C are in motion. Ship A moves relative to B is with speed v towards North east Ship B moves relative to C with speed v towards the North-West. Then relative to A. C will be moving towards :-

• A. North
• B. South
• C. East
• D. West

Answer 1

The correct option is B South

Let W-E direction is x, and S-N direction is y.

From the first condition,

V_a−V_b=1/√2(iˆ+jˆ)

1/√2(iˆ+jˆ) is a unit vector along the NE direction.

From the second condition,

V_b−V_c=1/√2(−iˆ+jˆ)

1/√2(−iˆ+jˆ) is a unit vector along the NW direction.

A velocity of C wrt A is

V_c−V_a.=(V_c−V_b)−(V_a−V_b)=1/√2(iˆ−jˆ)−1/√2(iˆ+jˆ)=−2‾√vjˆ

SoC is moving toward South wrt A