Question

Two forces, each numerically equal to 5 N, are acting as shown in the figure. Find the angle between forces?

• A. 60°
• B. 120°
• C. 30°
• D. 150°

Answer 1

Answer: (B)

120°

Answer 2

The figure shows two forces originating from a common point. One force is horizontal and pointing to the right, with magnitude 5N. The other force is pointing upwards and to the left, with magnitude 5N. The angle shown as 60° is between the horizontal line and the second force vector.

Assuming the horizontal force is along the positive x-axis, the other force is in the second quadrant. The angle 60° is the angle between the negative x-axis and the second force. The angle between the positive x-axis and the negative x-axis is 180°. Therefore, the angle between the positive x-axis and the second force is $180° - 60° = 120°$.

The angle between the two forces is the angle between their directions, which is 120°.