Q.
Let the value of acceleration due to gravity at poles and equator of earth gp and ge respectively. Assuming the earth to be a sphere of radius R rotating about its axis with angular speed ω then gp−ge is given by:
Effective value of acceleration due to gravity (gϕ) is given by gϕ=g(1−gω2Rcos2ϕ)
where ω is angular velocity.
At poles: ϕ=90∘ ∴gϕ=gp=g… (i)
At equator ϕ=0gϕ=ge=g(1−gω2R)=g−ω2R… (ii)
From Eqs. (i) and (ii), we get ∴gp−ge=g−(g−ω2R)=ω2R