A spacecraft is powered by electricity generated by the heat produced when 23894Pu decays with a half-life of 87.75 y. Engineers predict that the spacecraft will have insufficient power to operate its instruments when the amount of 238 94Pu in its power generators drops below 67 % of the amount it had at launch on September 1, 1977 Required:
In what year will its instruments cease to function?

Agas contained within a piston-cylinder assembly undergoes three processes in series: process 12: compression with pv= constant from 1 bar and 1 liter to 4 bar. process 23: constant pressure expansion to 1 liter. process 31: constant volume calculate the pressure and volume at each state, and sketch the processes on a p-vdiagram labeled with pressure and volume values at each numbered stat

The average density of the planet uranus is 1.27 103 kg/m3. the ratio of the mass of neptune to that of uranus is 1.19. the ratio of the radius of neptune to that of uranus is 0.969. find the average density of neptune.

Wind and moving water provide energy. question 1 options: chemical mechanical thermal none of the above