Kinematics Question 513
Question: A particle is projected from point $ O $ with velocity $ u $ in a direction making an angle $ \alpha $ with the horizontal. At any instant is position is at point $ p $ at right angles to the initial direction of projection, it’s velocity at point $ p $ it’s
Options:
A) $ u\tan \alpha $
B) $ u\cot \alpha $
C) $ ucosec\alpha $
D) $ u\sec \alpha $
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Answer:
Correct Answer: B
Solution:
[b] Horizontal velocity at point ‘[O’=u cos$ \alpha $
Horizontal velocity at point ‘P’=v sin $ \alpha $
In projectile motion horizontal component of velocity remains constant throughout the motion
$ \therefore v\sin \alpha =u\cos \alpha $
$ \Rightarrow v=u\cot \alpha $
