In 1940, it was discovered that uranium could be artificially changed to plutonium, a process called transmutation. What combination of decay processes would convert U-239 (92 protons) into Pu-239 (94 protons)? A. Beta-decay followed by beta decay.
B. Positron emission followed by electron capture.
C. Electron capture followed by alpha decay.
D. Alpha decay followed by beta decay.

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )