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Physics · MOTION IN A PLANE
हिन्दीA motorboat is racing towards north at \( 25\text{ km/h} \) and the water current in that region is \( 10\text{ km/h} \) in the direction of \( 60^\circ \) east of south. What is the magnitude of the resultant velocity of the boat?
Correct answer · Option 2
\( 22\text{ km/h} \)
Explanation
Angle between motorboat velocity (North) and water current (\( 60^\circ \) E of S) is \( \theta = 180^\circ - 60^\circ = 120^\circ \). Resultant \( R = \sqrt{25^2 + 10^2 + 2(25)(10)\cos 120^\circ} = \sqrt{625 + 100 - 250} = \sqrt{475} \approx 22\text{ km/h} \).
