A body of mass $10 \mathrm{~g}$ is tied to a string of length $0.4 \mathrm{~m}$ and it is whirled in a…
A body of mass $10 \mathrm{~g}$ is tied to a string of length $0.4 \mathrm{~m}$ and it is whirled in a horizontal plane with a speed of $6 \mathrm{~ms}^{-1}$. Then the tension in the string is
$1.9 \mathrm{~N}$
$36 \mathrm{~N}$
$0.9 \mathrm{~N}$
$3.6 \mathrm{~N}$
Solution
Mass of body, $\mathrm{m}=\log =10 \times 10^{-3} \mathrm{~kg}$ length of string, $\mathrm{L}=0.4 \mathrm{~m}$ speed, $v=6 \mathrm{~m} / \mathrm{s}$ In horizontal plane
Tension, $\mathrm{T}=\frac{\mathrm{mv}^2}{\mathrm{r}}$
Here, length of string $=$ radius of string $\mathrm{T}=\frac{10^{-2} \times(6)^2}{0.4}=0.9 \mathrm{~N}$