Question

If the pendulum is allowed to continue to swing, it will eventually come to a stop. explain why.

Answer 1

Kinetic energy is transferred into the next object 

Answer 2

Pendulum works on the bases that the kinetic energy is transferred into the next object and that energy cannot be created but only transferred (basic stuff), as long as the kinetic energy isn't lost, it'll swing forever however this isn't true. The Kinetic energy can be transformed into sound energy and heat energy thus it'll eventually run out of energy.