According to the law of conservation of energy the total amount of energy in the universe does not change but remains constant true or false ?

4

explanation:

4

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.

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray