A) (i) 10 J (ii) -8.75 J
B) (i) -10 J (ii) -8.25 J
C) (i) 1.25 J (ii) -8.25 J
D) (i) 100 J (ii) 8.75 J
Correct Answer: A
Solution :
\[{{w}_{g}}{{w}_{a}}={{K}_{f}}-{{K}_{i}}\] \[mgh+{{w}_{a}}=\frac{1}{2}m{{v}^{2}}-0\] \[{{10}^{-3}}\times 10\times {{10}^{3}}+{{w}_{a}}=\frac{1}{2}\times {{10}^{-3}}\times {{(50)}^{2}}\] \[{{w}_{a}}=-8.75\,J\]i.e. work done due to air resistance and work done due to gravity = 10 J
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