The gravitational field in a region is given by g → = 5 i ^ + 12 j ^   N   kg - 1 . The…

The gravitational field in a region is given by g→=5i^+12j^ N kg-1. The change in the gravitational potential energy of a particle of mass 2 kg when it is taken from the origin to a point 7 m,-3 m is
  1. 71  J
  2. 1 3 5 8  J
  3. 2  J
  4. 1  J

Solution

dV=-g→.dr→

⇒∆V=-g→.∆r→
             =-5i^+12j^·7i^-3j^
              = - 3 5 - 3 6 = 1

⇒ΔU=mΔV=2J

Asked in: JEE Main 2014 (19 Apr Online)

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