What are strata and how are they arranged?

The method of reading the order is called stratigraphy (layers of rock are called strata). ... Sedimentary rocks are normally laid down in order, one on top of another. In a sequence, the oldest is at the bottom, the youngest is at the top. This is the principle of 'superposition'.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.