Azhagu The Super Cop

Azhagu the super cop was chasing a super thief which had special powers because of which the thief can fly but at a constant height h h from the ground. After too too much of runing the thief gets tired and stops, seeing this Azhagu fires a bullet with some angle from ground having max. height 3 h 3h .The bullet should have hit the thief.

But as soon as the bullet left the gun the thief starts to run once again with a constant velocity v m s 1 v \ ms^{-1} , but still Super Cop Azhagu's bullet hit's the thief .

Then the ratio of v v and horizontal velocity of bullet is of the form 2 k 1 + k \dfrac {2k}{1+k} .

Find the value of 3 k 2 3k^{2} .

Note:

  • Assume all the conditions to be ideal
  • Azhagu is on ground and the thief is flying at every instant of time
  • Bullet missed the target once.
Extra Credit :- If Azhagu is the super cop then who is the thief ???


The answer is 2.

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2 solutions

Murlidhar Sharma
May 21, 2015

We can assumue t 1 t_{1} and t 2 t_{2} to be two instants of time for which the particle is at height h h .

Substituting u sin θ = 6 g h u*\sin \theta= \sqrt{6*g*h} in the equation for h h we get a quadratic which gives two values of t i.e. t 1 t_{1} and t 2 t_{2} . Here t 2 > t 1 t_{2}>t_{1} .

Now the distance travelled by particle is u cos θ t 2 u*\cos \theta*t_{2} . Which is equal to u cos θ t 1 + v t 2 u*\cos \theta*t_{1} + v*t_{2} . Here u c o s ( t h e t a ) t 1 u*cos(theta)*t1 is the initial horizontal distance between them.

Equating them we get ( v / u cos θ ) = 4 / ( 6 + 2 ) = 2 k / ( k + 1 ) (v/u*\cos \theta)=4/(\sqrt{6}+2)=2*k/(k+1) .

Hence k = 2 / 3 k=\sqrt{2/3}

Did the same way.....!

Samarth Agarwal - 6 years ago

Who's the thief then?

Kishore S. Shenoy - 5 years, 9 months ago

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Guess who ??

Shubhendra Singh - 5 years, 9 months ago

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IDK!! Say!

Kishore S. Shenoy - 5 years, 9 months ago

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@Kishore S. Shenoy Even I don't know so let's just forget it.

Shubhendra Singh - 5 years, 9 months ago
Ashish Jog
May 19, 2015

Good One!!!

Thanks, but I don't think that it's the solution

Shubhendra Singh - 6 years ago

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