Question

A .1 kg mass is attached to a string 75 cm long and swings in a horizontal circle, revolving once every .8s. calculate the tension of the string.

Answer 1

4.62N

Step-by-step explanation:

Since the motion covers 1 circle (or 2π rad) per 0.8 seconds, its angular velocity is

`\omega=2\pi/0.8 = 7.85 rad/s`

Radius of the circular motion is r = 75 cm or 0.75m. We can calculate the centripetal acceleration of this mass

`a_c = \omega^2r = 7.85^2 * 0.75 = 46.2 m/s^2`

From Newton's 2nd law, we calculate the centripetal force, which is also the tension of the string:

`F_c = a_cm = 46.2 * 0.1 = 4.62 N`