Describe how physical and chemical changes are different. how are they similar?

Well a chemical change is when substances are combined and the final product is permanent

For example ... baking a cake is a chemical change because the ingredients in the cake can't be separated as separate substances like they were in the beginning

A physical change is where the substances isn't changes, but just the appearance.

For example... origami or cutting paper is considered a physical change because even though it was cut or folded it is still paper.  

One similarity is that the physical and chemical changes are categorized under characteristic changes

-+ Hope I helped +-

the correct answer is a

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.