Ali’s family has a farm near the coast. Winds are constantly carrying away soil during the winter when no crops are growing. What can ali suggest as a way to prevent wind erosion of the soil? A. Plant a row of trees between the fields in the ocean.

B. water the soil more frequently to keep it from blowing away

C. build a barbed wire fence around the perimeter of the fields.

D. apply more fertilizer to the plants to make them grow bigger.

The lights used by mark watley (played by matt damon) during the film the martian seem to be metal halide lamps. metal halide lamps are filled with vaporized mercury and metal-halogen compounds. when an electric current is passed through the lamp, the tube begins to glow a bright white/blue color. if you were to pass this light through a prism to separate the individual light frequencies, you would see a rainbow just as you would if using natural sunlight because of the complexity of the metal halide gas and the vast amount of possible electron transitions. (the study of light in this way is known as spectroscopy and allows astronomers to know exactly what atoms compose distant stars, simply by looking at the light they emit. the spectral lines an atom produces uniquely identifies that atom just like a fingerprint uniquely identifies a person. the momentum equation and energy equation that we have used above can be combined to give the following equation: c = e p where again p is the phonon momentum, e is the photon energy and c is the speed of light. when you divide the photon energy found in #6 by the photon momentum found in #4, do you get the speed of light? (if not, check your work for questions #4 through #6). yes no

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron