goIIT: IIT JEE AIEEE CET WBJEE VITJEE BITSAT IIIT AICET Engineering Entrance Experts, Student Discussion Community, IIT JEE Preparation Online

The approach given by Jatinpreet is conceptually correct:
When final velocity vector is perpendicular to initial velocity vector,
U.V = 0 ---- (1)
If t₁ is the time elapsed until Y component of velocity is zero,
then 0 = 10 Sin30 - gt₁

t₁ = sin30 = 1/2 sec.

If t₂ be the additional time till velocity vector becomes perpendicular to the initial,
V = 10 Cos30 i - gt₂ j ---- (2)
Now, U = 10 Cos30 i + 10 Sin30 j ---- (3)

From (1), (2), and (3) above, we have,
(10 Cos30)² - (10 Sin30)gt₂= 0
Therefore, t₂ = 3/2 sec
Hence total time elapsed = t₁ + t₂ = 2 sec.

But, total time of flight = (2x10xsin30)/g = 1 sec.
Therefore, such a situation will not be reached when the vectors will be perpendicular.

Hi there,

Revision is the key to performance on the final day of exam! For a complete course revision (physics, chemistry and maths), one must keep at least 4 months before the exam. This is the time when you should try and solve as many new problems as well apart from revisiting theoretical concepts and formulae, etc.

Mark important things in your book/notebook as you study them for the first time, so that you know what exactly to revise more when the revision time comes.

Your planning seems alright. Good luck.

Silicon, like carbon is a p-block element of group IV, lying directly below carbon in the periodic table of elements, so that much of its basic chemistry is similar. For instance, just as carbon forms chloroform (CHCl₃) , silicon yields silicon chloroform (SiHCl₃).