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A stream of glass beads, each with a mas...

A stream of glass beads, each with a mass of 15 gram, comes out of a horizontal tube at a rate of 100 per second. The beads fals a distance of `5m` to a balance pan and bounce back to their original height. How much mass (in kg) must be placed in the other pan of the balance to keep in pointer at zero?

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The correct Answer is:
3
`/_\vecp` (change in momentum per collision)
`=2msqrt(2gh)=2xx15xx10^(-3)(10)=0.3kg ms^(-1)`
Then i `/_\p_(100)` ( in 1 second) `=30kgms^(-1)`
Force exerted `=30N`
So weight requried `=30N`. So mass `=3kg`
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