The kinetic energy \[k\] of a particle moving along a circle of radius \[R\] depends on the distance covered \[s\] as \[k=a{{s}^{2}}\] where \[a\] is a constant. The force acting on the particle is [MNR 1992; JIPMER 2001, 02; AMU (Engg.) 1999]

• A.             \[2a\frac{{{s}^{2}}}{R}\]  
• B.   \[2as{{\left( 1+\frac{{{s}^{2}}}{{{R}^{2}}} \right)}^{1/2}}\]
• C.             \[2as\] 
• D.             \[2a\frac{{{R}^{2}}}{s}\]