IIT JEE : Question [Kinematics ( + Rotation )] from Arihant

Q: A light rod is placed on a smooth horizontal surface . Initially , the end A begins to move vertically upward with constant velocity v0 and centre of the rod upward with a velocity v02 having downward acceleration a02 , the other end moves downward with :

[A] zero initial velocity having zero acceleration
[B] zero initial velocity having a0 acceleration
[C] non-zero initial velocity having zero acceleration
[D] none of the above

ANSWER GIVEN IN ARIHANT : B

PLEASE EXPLAIN AS TO HOW TO SOLVE THIS QUESTION AND WHAT CONCEPT DO WE USE...I THINK THAT THIS QUESTION USES ONLY KINEMATICS CONCEPTS AND ROTATION IS NOT NEEDED .

7 Answers

1
The Enlightened One - jsg ·

Come on , someone pls tell the answer and its reason....is it such a hard question.....??!!! [7]

1
The Enlightened One - jsg ·

SO NO ONE KNOWS THIS QUESTIONS' ANSWER ?????? [5]

1
rickde ·

oops din't see q properly

see rod is rotating the velocity of center is Vo/2 upwards
velocity of one end is Vo/2 + Vo/2
velocity of other end is Vo/2 - Vo/2 = 0

similarly for accln

accln = Ao/2 + Ao/2 = A

hence b

1
The Enlightened One - jsg ·

thanks a lot , rickde..!

1
cipher1729 ·

the velocity part is allright. but can someone please explain to me the acceleration part???
If we use the concept of IAOR , we find that it(IAOR) lies on the other end of rod(for which we have to find everything). So shouldnt velocity and acc BOTH be 0 for that end??
[7]

1
rickde ·

@ cipher see the direction of acc

1
cipher1729 ·

oops sorry!!

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