Laws of Motion - Result Question 57
57. Two stones of masses $m$ and $2 m$ are whirled in horizontal circles, the heavier one in radius $\frac{r}{2}$ and the lighter one in radius $r$. The tangential speed of lighter stone is $n$ times that of the value of heavier stone when they experience same centripetal forces. The value of $n$ is : [2015 RS]
(a) 3
(b) 4
(c) 1
(d) 2
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Answer:
Correct Answer: 57. (d)
Solution:
- (d) According to question, two stones experience same centripetal force
i.e., $F _{C_1}=F _{C_2}$
or, $\frac{mv_1^{2}}{r}=\frac{2 mv_2^{2}}{(r / 2)} \quad$ or, $V_1^{2}=4 V_2^{2}$
So, $V_1=2 V_2$ i.e., $n=2$
