Infinite no.of bodies, each of mass 3kg are situated at distances 1m, 2m, 4m, 8m....... respectively on x-axis. The resultant intensity of gravitational field at the origin will be
4G
Intensity at the origin =GMr21+GMr22+GMr23+GMr24+......
=GM[1+14+116+116+164+......]=GM(11−14)==GM×43=G×3×43=4G [As M=3kg given]