passwella.
Menu

JAMB Mathematics 1978 Question 21

Question 21

Vectors and Transformations

A force of 5 units acts on a particle in the direction to the east and another force of 4 units acts on the particle in the direction north-east. The resultant of the two forces is

  1. A.√3 units
  2. B.3 units
  3. C.√(41 + 20√2) units
  4. D.√(41 − 20√2) units
  5. E.√(41√2 + 20) units.
Show the answer and explanation

Answer: C (√(41 + 20√2) units)

Explanation

The angle between the forces is 45°, so R² = 5² + 4² + 2(5)(4)cos 45° = 41 + 20√2.