A mass of 2kg is dropped from rest at a height of 10m. i) What is the initial GPE of the mass? ii) What is the final velocity of the mass when it hits the ground?
Part iGravitational Potential Energy (GPE) = mass x gravitational acceleration constant x heightGPE = 2 x 9.81 x 10 = 196.2JPart iiConservation of energy states that the sum of the GPE and KE at the intial position is equal to the sum of the GPE and KE at the final position.GPE1 + KE1 = GPE2 + KE2(KE = 0.5 x m x v2)As the mass is released from rest the initial velocity is 0, KE1 = 0.As the mass is 0m above the ground in the final position, GPE2 = 0.So, GPE1 = KE2mgh = 0.5mv2196.2 = 0.5(2)(v2)v2 = 196.2v = 14ms-1
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