The half-life for a 400-gram sample of radioactive element X is 3 days. How much of element X remains after 15 days have passed? A.
12.5 g

B.
25 g

C.
50 g

D.
100 g

1) sections 1, 2, and 10 are significant primarily because they suggest the likelihood that a) widow wycherly is actually the woman in the full-length portrait. b) dr. heidegger wants to include his guests in an experiment with the water. c) dr. heidegger plans to drink some of the water from the vase and needs witnesses. d) the guests will be asked to witness dr. heidegger's transformation when he drinks the water.

Which atomic model was proposed as a result of j. j. thomson’s work?

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? how far will the football travel before it lands?