Which force is a noncontact force? (15 points)
A.
magnetic force
B.
frictional force
C.
normal force
D.
impact force

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

Suppose that recording station n is located 200 km north of the epicenter of an earthquake, and recording station s is located 100 km south of the epicenter of the same earthquake. which of the following statements would be true?

In which of the following cases is work being done on an object? question 2 options: pushing against a locked door carrying a box down a corridor pulling a trailer up a hill suspending a heavy weight with a strong chain