Two forces act at a point and are such that if the direction of one is reversed, the resultant is turned through a right angle. Show that the two forces must be equal in magnitude.

Explanation

To solve the problem, we will follow these steps:

### Step 1: Define the Forces
Let the two forces be represented as vectors \( \vec{A} \) and \( \vec{B} \).

### Step 2: Resultant of the Forces
The resultant of the two forces when both are acting in the same direction is given by:
\[
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