Alimb with mass 14 kg falls out of a tree from a height of 3.5 m. how much mechanical energy does the limb have just before it hits the ground? (assume there is no air resistance.) a. 480.2 j b. 355.3 j c. 0 j d. 49 j

While the limb is still on the tree on the height h=3.5 m, it has only potential energy Ep=m*g*h where m is the mass, g=9.81 m/s² and h is the height. While it is falling down its potential energy is converting into kinetic energy Ek=(1/2)*m*v², where m is mass and v is the velocity. The moment before it hits the ground the entire potential energy is converted into kinetic energy: 

Ek=Ep=m*g*h=14*9.81*3.5=480.69 J.

So the correct answer is A. 480.2 J 

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