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A man throws the bricks to a height 12m ...

A man throws the bricks to a height `12m` where they reach with speed `12m//s`.If the throws the brick to just reach `12m` what percentage energy he will save?

A

`|vec(v)_(A//"Raft")|=|vec(v)_(B//"Raft")|` and `|vec(v)_(A//"ground")|lt|vec(v)_(B//"ground")|`

B

`|vec(v)_(A//"Raft")|=|vec(v)_(B//"Raft")|` and `|vec(v)_(A//"ground")|gt|vec(v)_(B//"ground")|`

C

`|vec(v)_(A//"Raft")|gt|vec(v)_(B//"Raft")|` and `|vec(v)_(A//"ground")|=|vec(v)_(B//"ground")|`

D

`|vec(v)_(A//"Raft")|=|vec(v)_(B//"Raft")|` and `|vec(v)_(A//"ground")|=|vec(v)_(B//"ground")|`

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