Which of the following describes half-life? Choose which apply. A. Half-life is the amount of time it takes for half of a sample to decay.
B. The shorter the half-life, the more unstable the nuclide.
C. Half-life cannot be calculated for nuclides.
D. The longer the half-life, the more stable the nuclide

please answer correctly

Complete these sentences. if a roller coaster train has a potential energy of 1,500 j and a kinetic energy of 500 j as it starts to travel downhill, its total energy isj. once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 j, and its potential energy decreases to j. when the train reaches the bottom of the track and is traveling along the ground, its kinetic energy isj.