Question

A stone of mass 0.3 kg attached to a 1.5 m long string is whirled around in a horizontal circle at a speed of 6 ms. The tension in the string is

• A. 10 N
• B. 20 N
• C. 7.2 N
• D. 30 N

Answer 1

Answer: (C)

7.2 N

Answer 2

Here, mass of the stone m = 0.3 kg
Length of a string = 1.5 m
Speed v = 6 m/s
$T=\frac{mv^{2}}{R}=\frac{\left(0.3\right)\left(6\right)^{2}}{1.5}$ =7.2 N