Question

Two forces of magnitudes 3N and 4N respectively are acting on a body , calculate the resultant force if the angle between them is 0,180,90 degree..

Answer 1

Answer:

for angle 0 force=7N

for angle 180 force=1N in the direction of larger force

for angle 90 force =5N

Answer 2

Answer:

If θ = 0°, then the resultant vector's magnitude is 7 N.

If θ = 180°, then the resultant vector's magnitude is 1 N.

If θ = 90°, then the resultant vector's magnitude is 5 N.

Explanation:

USE BELOW IMAGES AS REFERENCE :

(i) If θ = 0°, then forces are parallel to each other.

So, resultant vector's magnitude = 3 + 4 => 7 N

It can also be solved by √(A² + B² + 2ABcosθ)

=> √(3² + 4² + 2(3)(4)cos0)

=> √(9 + 16 + 24(1))

=> √49 => 7 N

(ii) If θ = 180°, then forces will be opposite to each other.

So, resultant vector's magnitude = 4 - 3 => 1 N

This also can be solved by √(A² + B² + 2ABcosθ).

=> √(3² + 4² + 2(3)(4)cos180)

=> √(9 + 16 + 24(-1))

=> √25 -24 => √1 => 1 N

(iii) If θ = 90°, then forces are perpendicular to each other.

So, resultant vector's magnitude = √(A² + B² + 2ABcosθ)

=> √(3² + 4² + 2(3)(4)cos90)

=> √(9 + 16 + 24(0))

=> √25 => 5 N