There are other isotopes of cerium which are radioactive. Different isotopes of cerium have different half-lives.
The half-life of an isotope can be found by studying how the number of atoms
changes over time.
Figure 7 shows how the number of atoms of cerium-148 in a 120 g sample changes
over time.
1. Determine the ratio of the number of cerium atoms in the sample when it was 100 seconds old compared with when the sample was 350 seconds old. Use data from Figure 7.
2. Determine the activity of the sample of cerium when the sample was 20 seconds old. Use Figure 7.

The 20@kg wheel has a radius of gyration about its center g of kg = 300 mm. when it is subjected to a couple moment of m = 50 n # m, it rolls without slipping. determine the angular velocity of the wheel after its mass center g has traveled through a distance of sg = 20 m, starting from rest.

This problem has been solved! see the answera non-uniform fire escape ladder is 6.0m long whenextended to the icy alley below. it is held at the top by africtionless pivot, and there is neglibible frictional force fromthe icy surface at the bottom. the ladder weighs 250n, and it'scenter of gravity is 2.0m along the ladder from the bottom. amother and child of total weight 750n are on the ladder 1.5m fromthe pivot. the ladder makes an angle θ with the horizontal.find the magnitude and direction ofa) the force exerted by the icy alley on the ladderb) the force exerted by the ladder on the pivotc) do your answers in part a and b depend on the angle?

What type of nuclear decay causes the atomic number of an element to increase by 1?