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Q.4. A meter scale of mass 1 kg and thickness 2 cm is lying flat on the ground. When it is placed vertically the increase in potential energy is
Option:
  •  0.49 J
  •  0.48 J
  •  0.049 J
  •  4.9 J 

E potential= mgh = 1 x 9.8 x 2/100 = 0.196 J
this potential energy on the ground
you should mention the length of scale also to solve the question
  • -11
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It's meter scale So the change in potential energy will be MgH. H is the change in height of centre of mass. Center of mass of a uniform body is its midpoint. So Delta p.e =mgH =1×9.8×1/2 =4.9J
  • 2
A beed starts sliding from A on a frictionless wire with initial velocity of 4m per second. On reaching C it's velocity will be (g=10)
  • -6
It's meter scale So the change in potential energy will be MgH. H is the change in height of centre of mass. Center of mass of a uniform body is its midpoint. So Delta p.e =mgH =1×9.8×1/2 =4.9J
  • 0
all replied given answers are wrong 
the mentioned that the thichness of the scale is 2cm that is 2/1000m
tha implies change in cetrwe of masss is 498/1000m 
that implies workdone= mgh=1 x9.8x 498/1000=0.48joule
 
  • 1
yaseen they said it is meter scale that is lenght is 1metre
 
  • 0
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