Zach listed the process of how laser beams are produced with crystals. A flashlamp pumps energy through the crystal. Atoms in the crystal absorb and then release some of the energy as light. Light bounces off mirrors and occasionally bounces off crystal atoms, increasing in energy. Some light escapes the tube through the highly reflective mirror, forming a concentrated beam. Which best describes Zach's error?

c

explanation:

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.

increase masses, decrease separation

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2