At what point is the half-life of a radioactive isotope reached? A. When half the parent nuclei in a sample have become daughter nuclei
B. When all the daughter nuclei in a sample have become parent nuclei
C. When half the daughter nuclei in a sample have become parent nuclei
D. When all the parent nuclei in a sample have become daughter nuclei

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field

16. a brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800 n on him. the mass of the losing player plus equipment is 90.0 kg, and he is accelerating at 1.20m/s2 size 12{1 "." "20"" m/s" rsup { size 8{2} } } {} backward. (a) what is the force of friction between the losing player’s feet and the grass? (b) what force does the winning player exert on the ground to move forward if his mass plus equipment is 110 kg? (c) draw a sketch of the situation showing the system of interest used to solve each part. for this situation, draw a free-body diagram and write the net force equation.

With physics question #5? for any !