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A body weighing 20 g has a velcoity `8cms^(-1)` after one second of its starting from mean position. If the time period is 8 seconds, find the kinetic energy, potential energy and total energy. |
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Answer» Here, `m=20g, T=8s, omega=(2pi)/(T)=(2pi)/(8)=(pi)/(4)rad//s` When `t=1s, v=8cms^(-1)` Now, `v=Aomega cos omega t` `8=Axx(pi)/(4) cos ((pi)/(4)xx1)=A xx(pi)/(4)xx(1)/(sqrt(2))` or `A=(32sqrt(2))/(pi)` Total energy `=(1)/(2)momega^(2)A^(2)` `=(1)/(2)xx20xx((pi)/(4))^(2)xx((32sqrt(2))/(pi))^(2)=1280 ergs` Kinetic energy `=(1)/(2)mv^(2)=(1)/(2)xx20xx8^(2)=640erg` `PE= ` Total energy `-` Kinetic energy `=1280-640=640erg` |
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