Question

76. A particle is attached to a string of length land is
released from horizontal position as shown. On
reaching to lowest point it collides with another
identical particle at rest. If the collision is perfectly
inelastic then the height upto which the combined
mass will rise after collision is :-

1) L
2) L/2
3)L/4
4)L/8​

Answer 1

Answer:

The correct answer is 3)L/4

Explanation:

From the above question,

Let the collision take place at t sec and s1 and s2 be the distance traveled by the masses just before collision.

Thus we get:

      −s1=−21gt2 and s2=20t−21gt2

Thus we get:

        s1+s2=20t

        t=1 sec

Thus, s2=20(1)−2110(1)2=15 m

Now we will calculate the velocity of the masses just before collision

v1=0−gt=−10 m/s and v2=20−gt=10 m/s

Now as the collision is inelastic, we have

mv1+mv2=(m+m)v

Thus we get the velocity of the combined mass as 0.

Thus we see that the combined mass does not have any velocity and it would start falling downwards after the collision. Thus the maximum height reached is 15 m.

A smaller mass approaching a larger mass will bounce back in a collision. If a larger mass is intially moving toward a smaller mass, both will continue with momentum in the direction of the intial momentum.

For more related question : https://brainly.in/question/8997

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