This type of circuit is a closed series circuit
Base on my research, within 2 hours you have a number of atoms which remain.
N= N0*2^(-t/6.020 = N= N0*2^-0.33223= 07943 N0
So, the number of atoms that are being disintegrated is N0-N=N0*(1-0.79430)=0.2057 N0
It must be equal to 15 mCi = 15*3.7*10^7= 5.55*10^8 atoms
N0= 5.55*10*8/0.2057 = 2.698*10^9 atoms
Therefore, 2.698*10^9 atoms is the number of N0
A cyclist must lean into a turn to prevent tipping over in the other direction.The frictional force provides the centripetal force necessary to turn the cyclist to the left.But the frictional force also produces a clockwise torque that will cause the rider and the bicycle to tip clockwise to the right.The force is provided by the friction of the tires.
Potential energy is when the roller coaster rises. Kinetic energy is when the roller coaster declines.