Natural potassium contains 40k, which has a half-life of 1.277 ✕ 109 y. what mass (in g) of 40k in a person would have a decay rate of 4180 bq? g (b) what is the fraction of 40k in natural potassium, given the person has 136 g in his body?

Wo small variable-thrust jets are actuated to keep the spacecraft angular velocity about the z-axis constant at ? 0 = 1.16 rad/s as the two telescoping booms are extended from r1 = 1.18 m to r2 = 4.69 m at a constant rate over a period of 124 seconds. the small 19-kg experiment modules at the ends of the booms may be treated as particles, and the mass of the rigid booms is negligible. determine the necessary thrust t for each jet as a function of time where t = 0 is the time when the telescoping action is begun. after you have the general expression for t, answer the questions. show work.