1. Professor Curie is using the radioactive isotope Francium-223 in her research. This Isotope has a half-life of 22 minutes, which means that every 22 minutes the sample has half the radioactivity it did in the previous interval. If Professor Curle has 15 grams of Francium-223, which explicit formula describes how the isotope decays?
O = 22(0.5) -
O = 15(22)"-1
O=15(0.5)-1
O = 22(0-5)-2

c

step-by-step explanation:

7.9m and 4.3°

step-by-step explanation:

let east be +x and north be +y, x = distance * cos θ, y = distance * sin θ  

for 3.5 south, y = -3.5  

for 8.2, x = 8.2 * cos 30 and y = 8.2 * sin 30  

for 15 west, x = -15  

total x = 8.2 * cos 30 – 15 ≈ -7.9  

total y = -3.5 + 8.2 * sin 30 = 0.6  

magnitude = [(8.2 * cos 30 – 15)^2 + 0.6^2)]^0.5  

the magnitude is approximately 7.9 m  

tan θ = y/x = 0.6/-7.9  

the angle is approximately 4.3˚ north of west