In which direction is the kinetic friction force on block 1 in the figure?.

moving ball hits still ball. mover stops, hit ball moves. momentum transfer.

measure their densities same density, same sub

no. bullets are macro objects. wave nature is for light waves, extremely tiny particles. if a light particle was the size of your finger, the bullet would be the size of the universe. so basically, that huge difference in size makes the wave nature of matter insignificant.