Kinematics Question 35
Question: The maximum and minimum magnitude of the resultant of two given vectors are 17 unit and 7 unit respectively. If these two vectors are at right angles to each other, the magnitude of their resultant is [Kerala CET (Engg.) 2000]
Options:
A) 14
B) 16
C) 18
D) 13
Show Answer
Answer:
Correct Answer: D
Solution:
$ {R _{\max }}=A+B=17 $ when $ \theta =0{}^\circ $
$ {R _{\min }}=A-B=7 $ when $ \theta =180{}^\circ $
by solving we get $ A=12 $ and $ B=5 $
Now when $ \theta =90{}^\circ $ then $ R=\sqrt{A^{2}+B^{2}} $
therefore $ R=\sqrt{{{(12)}^{2}}+{{(5)}^{2}}} $
$ =\sqrt{169} $
$ =13 $
BETA
