Work Energy and Power - Result Question 12
14. 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
Topic 2: Energy
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Answer:
Correct Answer: 14. (b)
Solution:
(b) $W=\Delta E=\frac{1}{2} m(v_1^{2}-v_2^{2})$
$=\frac{1}{2} \times 0.01[(1000)^{2}-(500)^{2}]=3750 J$.
