Calculate the minimum energy that a bird of mass 25g must expend to reach a height of 50m?

Question

Calculate the minimum energy that a bird of mass 25g must expend to reach a height of 50m?

Answer 1

Actually its 25/1000 x 10 x 50. (The weight has to be written in kg not g before multiplying by 10Newton/kg)

25/1000 x 10 x 50 = 12.5Joules.

( a really clever answer will use 9.81 instead of 10 but I don't want to do that in my head right now!)

Hope thats alright

Answer 2

Are you referring to an unladen swallow?  A swallow laden with a cocoa nut would travel much more slowly...  

Answer 3

I am going to put this answer in units of joules. therefore,

we must convert 25g to kg, which gives .025kg

as the bird ascends 50m, the potential energy would be

mgh=12.2625 j

since we are neglecting air friction and motion in other dimensions, the bird will use a little more than 12.2625 j to reach that height.

Answer 4

mgh= 25x10x50 = 12500 J