Question

A body of mass 1 kg is thrown upwards with a velocity 20 m s−1. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (Take g  = 10ms–2 )

 

a) 20 J              

b) 30 J            

c) 40 J               

d) 10 J

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Answer 1

Answer:

Initial energy =0.5×m×v^2

=0.5×1×20^2

=200J

Fianl energy = mgh

=1×10×18=180J

Loss in energy =200−180

=20J

hope it will help you.....