here as we know that there is no frictional loss
so here we will have sum of gravitational potential energy and kinetic energy will remain constant
so we can say that
[tex]U_i = K_f[/tex]
at initial point gravitational potential energy must be equal to maximum kinetic energy at its mean position
so now we will have
[tex]KE_{max} = mgL(1-cos\theta)[/tex]
here we know that
m = 2kg
L = 80 cm
[tex]\theta = 60 degree[/tex]
now from above equation
[tex]KE_{max} = 2(9.8)(0.80)(1 - cos60)[/tex]
[tex]KE_{max} = 7.84 J[/tex]
