passwella.
Menu

JAMB Physics 1980 Question 27

Question 27

Scalars and Vectors

A tugboat is travelling from Asaba to Onitsha across the River Niger with a resultant velocity of 20 knots. If the river flows at 12 knots, the direction of motion of the boat relative to the direction of water flow is

  1. A.36.87°
  2. B.53.13°
  3. C.90°
  4. D.136.87°
  5. E.143.13°.
Show the answer and explanation

Answer: B (53.13°)

Explanation

The resultant (20 knots) is the hypotenuse, with the 12-knot river flow as the side next to the angle: cos θ = 12/20 = 0.6, so θ = 53.13°.