A) 20 J
B) 30 J
C) 40 J
D) 10 J
Correct Answer: A
Solution :
The energy lost due to air friction is equal to difference of initial kinetic energy and final potential energy. Initially body possesses only kinetic energy and after attaining a height the kinetic energy is zero Therefore, loss of energy = KE - PE \[=\frac{1}{2}m{{v}^{2}}-mgh\] \[=\frac{1}{2}\times 1\times 400-1\times 18\times 10\] \[=200-180=20\,J\]You need to login to perform this action.
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