When a muscle contracts, it performs work. it does this by a) converting chemical energy to mechanical energy. b) converting mechanical energy into heat energy. c) converting mass into energy. d) creating energy.

A) converting chemical energy to mechanical energy.

When a muscle contracts, it performs mechanical work. The chemical energy generated in the muscle cell gets converted to mechanical energy. The oxidation of carbohydrates and fats helps in contraction of muscles. The metabolic process generates ATP molecules which is a storehouse of energy. during contraction. These molecules break to generate energy.

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.