K.C.S.E Physics Q & A - MODEL 2001PP1QN03

K.C.S.E Physics Q & A - MODEL 2001PP1QN03

 Fig 3 shows two identical hollow spheres. Spheres A is completely filled with the liquid while B is partly filled with identical liquid.

​When the two spheres are rolled gently on a horizontal surface. It is observed that the sphere B stops earlier that the sphere A. Explain this observation.

answer

• Centre of gravity of A is at (geometric) centre while that of B is lower when rolled. Centre of gravity of A stays in one position while that of B tends to be raised resisting motion as it resists; thus slowing down B. OR B there is friction force between the surfaces which resists motion.