Question

6. Two identical balls A and B are released from
the positions shown in figure. They collide
elastically on horizontal portion MN. The
ratio of the heights attained by A and B after
collision will be :-(neglect friction)
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Answer 1

Answer:

the answer will be 1:4

Explanation:

The solution is based on the diagram. According to the diagram the height of ball A from the ground is 4h and of ball B is h

Let the initial velocity of both A and B is u1 and u2

u1 = √2gh = √ 2 x g x 4h = √8gh

u2 = √2gh

Let the velocity of A and B after collision be v1 and v2

v1 = √2gh

v2 = √8gh

as their velocities are interchanged.

Now let A will go upto height x

Therefore,

mgx = m/2 x 2gh

x = h

Again let B will go upto height y

mgy = m/2 x 8gh

y = 4h

Therefore the ratio of the heights will be

x/y = h/4h = 1/4