Work Energy And Power Ques 7
7. A bullet of mass $10 $ $g$ leaves a rifle at an initial velocity of $1000$ $ m / s$ and strikes the earth at the same level with a velocity of $500$ $ m / s$. The work done in joules overcoming the resistance of air will be
[1989]
(a) $375$
(b) $3750$
(c) $5000$
(d) $500$
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Answer:
Correct Answer: 7.(b)
Solution:
- (b) $W=\Delta E=\frac{1}{2} m(v_1^{2}-v_2^{2})$
$=\frac{1}{2} \times 0.01[(1000)^{2}-(500)^{2}]=3750 $ $J$.
BETA
