Question

Two vectors have magnitudes 3 unit and 4 unit respectively. What should be the angle between them if the magnitude of the resultant is (a) 1 unit, (b) 5 unit and, (c) 7 unit.
Please explain briefly.

Answer 1

Explanation:

brief explanation...

a) when two forces are acted in the opposite direction the net force is minimum because the more magnitude forces cancel the less magnitude forces

here, 4-3=1

so the angle between them is 180°

b) when two forces act perpendicularly the resultant of the two forces is the whole root sum of their squares

I.e the pythagoras theorem is applied

here, whole root (4)^2+(3)^2=5

so the angle between them is 90°

c) when two forces act in the same direction the net force is maximum because the magnitude of forces add up

here, 4+3=7

so the angle between them is 0°

hope it helps.....