What can you conclude about the total mechanical energy of a pendulum as it swings back and forth?

The total mechanical energy of a pendulum is conserved neglecting the friction.

Explanation:

When a simple pendulum swings back and forth, it has some energy associated with its motion.The total energy of a simple pendulum in harmonic motion at any instant of time is equal to the sum of the potential and kinetic energy.The potential energy of the simple pendulum is given by P.E = mghThe kinetic energy of the simple pendulum is given by, K.E = 1/2mv²When the pendulum swings to one end, its velocity equals zero temporarily where the potential energy becomes maximum.When the pendulum reaches the vertical line, its velocity and kinetic energy become maximum.Hence, the total mechanical energy of a pendulum as it swings back and forth is conserved neglecting the resistance.