Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
Two forces, $F_1$ and $F_2$ are acting on a body. One force is double that of the other force and the resultant is equal to the greater force. Then the angle between the two forces is
PhysicsMathematics in PhysicsJEE Main
Options:
  • A $\cos ^{-1}(1 / 2)$
  • B $\cos ^{-1}(-1 / 2)$
  • C $\cos ^{-1}(-1 / 4)$
  • D $\cos ^{-1}(1 / 4)$
Solution:
1613 Upvotes Verified Answer
The correct answer is: $\cos ^{-1}(-1 / 4)$
Correct option is 3. $\cos ^{-1}(-1 / 4)$
Given
$F_1=F \quad F_2=2 F$ and
$F_R=2 F$
As we know
$F_R=\sqrt{F_1^2+F_2^2+2 F_1 F_2 \cos A}$
putting the above values, we get
$-F^2=4 F \cos A$
$\cos A=\frac{-1}{4}$
$A=\cos ^{-1}\left(\frac{-1}{4}\right)$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.