Answer:
The mass of the rock is  [tex]m = 2.46406 \ kg[/tex]
Explanation:
From the question we are told that
  The length of the string is  [tex]l = 0.96 \ m[/tex]
  The angular velocity is  [tex]w = 20.25 \ rad/s[/tex]
   The tension on the string is [tex]T = 970 \ N[/tex]
Generally the centripetal force acting on the rock is mathematically evaluated as
    [tex]T = mlw^2[/tex]
making m the subject of the formula
   [tex]m = \frac{T}{w^2 * l}[/tex]
substituting values
   [tex]m = \frac{970}{(20.25^2) * (0.96)}[/tex]
   [tex]m = 2.46406 \ kg[/tex]
   Â
