Q53 of 54 Page 135

An object of 50 kg mass is lifted from the earth surface to the height of 3 meters. Calculate its potential energy If this object is allowed to fall free then calculate its kinetic energy when it is at accurate half of the path.

Mass of the object (m) = 50 Kg


Height (h) = 3 m


Total potential energy = mgh


= 50 × 9.8 × 3


= 1470 J


According to the conservation of energy, the amount of potential energy lost is equal to the amount of kinetic energy gained.


So, the required kinetic energy is half the potential energy.


Hence, kinetic energy is





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