A004) Planetary Nebula/White Dwarf Stars - Little Ghost Nebula. Some red giant stars develop into planetary nebulas as their cores continue to contract, to increase in temperature, and to burn and vent the remaining gases into interstellar space. Eventually, the core collapses to the point where it is hot enough to ionize the vented gases, forming a relatively short-lived (~10,000-20,000 years) planetary nebula. The remaining core collapses into a white dwarf star. The vented materials from the planetary nebula play an important role in enriching the universe in elements with atomic weights less than 26 (forming the basis for carbon-based life like ourselves!). Which type of star will form a planetary nebula

Astudent looks at ocean waves coming into the beach. an ocean wave with more energy will a) have a greater height. b) have a greater period. c) travel toward the beach faster. d) strike the beach with greater frequency.

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?