Question

A string can withstand a tension of $25N$. What is the greatest speed at which a body of mass $1kg$ can be whirled in a horizontal circle using $1m$ length of the string?

• A. $10$ $m{s}^{-1}$
• B. $7.5$ $m{s}^{-1}$
• C. $5$ $m{s}^{-1}$
• D. $2.5$ $m{s}^{-1}$

Answer 1

Answer: (C)

$5$ $m{s}^{-1}$

Since the maximum force the string can withstand is $25N$. so:
$\frac{m{v_{max}}^2}{r}=25N$

$\Rightarrow \frac{1\times {v_{max}}^2}{1}=25N$

$\Rightarrow v_{max}=5m{s}^{-1}$