Question

Calculate the radial acceleration of an object on the ground at the earth's equator in m/s2, turning with the planet.

Answer 1

If it is sitting on the ground, the force up from the ground balances the centripetal acceleration and the gravitational force and the acceleration is zero.
If the question is what is the centrietal acceleration alone then use
Ac = v^2/r = w^2 r

w = 2 pi radians/24 hours = 2 pi /(24*3600)
r = earth radius

Answer 2

65