- #1

randomgamernerd

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## Homework Statement

:A stick of length L and mass M lies on a frictionless horizontal surface on which it is free to move in any way. A ball of mass m moving with speed v collides elastically with the rod at one of its extreme end( as shown in the figure). If after collision ball comes to rest, what should be the mass of the ball?

a) m= 2M

b)m=M

c)m=M/2

d)m=M/4[/B]

I have attached a pic of the figure

## Homework Equations

: Principle of conservation of mechanical energy(PCME) and principle of conservation of linear momentum(PCLM)[/B]

## The Attempt at a Solution

:From PCLM,[/B]

mv= MV

(where V= final velocity of the rod)

**From PCME,(as collision is elastic, we can conserve ME)**

1/2mv

^{2}=1/2MV

^{2}

**from these two equations I got m=M**

But the book says m=M/4

I wonder if we need to conserve angular momentum..but can't figure out how will conservimg angular momentum change the answer

Thanks for your help

Sorry for any grammatical error

Sorry if its a duplicate thread

But the book says m=M/4

I wonder if we need to conserve angular momentum..but can't figure out how will conservimg angular momentum change the answer

Thanks for your help

Sorry for any grammatical error

Sorry if its a duplicate thread