What happens the kinetic energy of the first domino when its hits the second domino?

When the first domino strikes the second domino, its kinetic energy is transferred to the second domino. This transfer occurs through the collision, where the first domino loses some of its kinetic energy, causing it to slow down, while the second domino gains kinetic energy and begins to move. The efficiency of this energy transfer depends on factors like the angle of impact and the materials of the dominoes, but ideally, the total energy is conserved in the system.