Physics Question

Archive SAT Subject Test Preparation
1

<p>From the Barron’s book:</p>

<p>As the angle between two concurrent forces increases, the magnitude of their resultant
(A) increases only
(B) decreases then increases
(C) increases then decreases
(D) remains the same
(E) decreases only</p>

<p>The correct answer is E, but I put B. The resultant force is highest when the two forces are in the same direction and decreases until 180 degrees, where the resultant is the smallest. Then from 180 degrees to 360 degrees, shouldn’t the resultant increase?</p>

2

<p>True, but keep in mind, when the angle between two vectors is more than 180 degrees, it is actually less than 180 degrees. For example, the angle between two forces can be 340 degrees, but they are actually 20 degrees apart (360 - 340 = 20). So think of 180 degrees as the “maximum” angle between any two vectors.</p>