Question

the diagram shows that the pendulums swing becomes lower and lower as the swinging continues. what best explains this phenomenon? the force of gravity acting on the pendulum becomes weaker over time. some of the pendulums energy is lost as heat. some of the pendulums energy is destroyed. the pendulum gains mass over time so it cannot swing as high.

Explanation:

According to the law of conservation of energy, energy is not destroyed but transformed. In a pendulum - system, air resistance and friction cause some of the mechanical energy to be converted into heat energy. The force of gravity remains constant near the Earth's surface and the mass of the pendulum does not change during its normal swinging motion.

Answer:

Some of the pendulum's energy is lost as heat.