A hollow hemisphere has a mass of 8kg and radius of 10cm. Gravitational force on a mass of 8kg at the center of hemisphere is (approx.)

Gravitational field intensity at the centre of hollow hemisphere is ,E=GM2R2E=G×8210×10−22 E=6.67×10−11×82×10−2=26.68×10−9 E=2.7×10−8N/kg ∴Gravitational force isF=m×E=8×2.7×10−8=21.6×10−8N