Question

A block of mass $2$ kg is tied to a string of length $2$ m, the other end of which is fixed. The block moved on a smooth horizontal table with constant speed $5$ m/s. Find the tension in the string.

• A. $30N$
• B. $25N$
• C. $10N$
• D. $40N$

Answer 1

The correct option is B $25N$

Answer is B.
In this case, the centripetal force is provided by tension.
That is, $T=\frac{m{v}^2}{r}=\frac{2\times 5^2}{2}=25N$.
Please refer the figure below.
Hence, the tension in the string is 25 N.