Which statement best defines Mechanical Energy? 1.Energy that is produced by an electrical current in a circuit.

2.Energy from the sun

3.The sum of an objects kinetic and potential energy

4.Energy that travels in waves due to vibrations.

Ais not a compound machine. a. bolt b. shovel c. handcart (dolly) d. see-saw (teeter totter)

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

Observations show that interstellar clouds can have almost any shape and