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An object of mass 40kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is halfway down. (Take g=10ms^(-2).) |
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Answer» Potential ENERGY `E_(p)=mgh` `=40kgxx10ms^(-2)xx5m` `=2000J` When it is allowed to fall, its potential energy gets converted into KINETIC energy. When the OBJECT is halfwary down `s=h=2.5m` Let its velocity be `vms^(-1)`. `v^(2)-u^(2)=2gh` `therefore v^(2)-(0)^(2)=2xx10xx2.5` `therefore v^(2)=50` Kinetic energy `E_(k)=(1)/(2)mv^(2)` `=(1)/(2)xx40xx50=1000J` |
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