InterviewSolution
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InterviewSolution
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A block of mas 2.0 kg is pulled up on a smooth incline of angle `30^0` with the horizontal. If the block moves wth an acceleration of `1.0 m/s^2`, find the power delivered by the pulling force at a time 4.0 s after the motion starts. What is the average power delivered during the 4.0 s after the motion starts? |
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Answer» Here, the given plane is smooth. Therefore, there is no force of friction. Now, `m=2kg,theta=30^(@), a=1m//s^(2),P=?` Force F applied up the plane is such that from figure., `F-mg sin theta =ma` `F=m(g sintheta +a)` `=2(9.8 sin 30^(@) +1)` `F=11.8N` From `v=u+at` `v=0+1xx4=4m//s` `:.` Power delivered by the force at a time 4 second after the motion starts is `P=Fxxv=11.8xx4=47.2 wat t` Now, displacement in 4 second is `s=ut+(1)/(2)at^(2)=0+(1)/(2)xx1xx4^(2)=8m` work done `= Fxxs=11.8xx8=94.4J` Average power delivered during 4 second after the motion starts `P=(W)/(t)=(94.4)/(4)=23.6"watt"` |
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