A ring-shaped weight with a radius of 40-cm is being spun
around its center axis for a physics demo. If experiments show that its moment of inertia is 0.4kg · m², what is the mass of the ring? m =___kg

Suppose you use a machine that gives you a mechanical advantage of 2 to achieve an output force of 30newtons what must the input force be

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

What do elements in a family tend to share. a.) similar periods b.) similar groups c.) similar atomic symbols d.) similar chemical properties and characteristics