Based on the law of conservation of mass, which of the following statements is correct? matter is neither created nor destroyed. matter can be created but it cannot be destroyed. the total mass of substances before a reaction is less than the total mass after a reaction. the total mass of substances before a reaction is greater than the total mass after a reaction.

The first statement (Matter is neither created nor destroyed) is correct.

The second statement would violate the law of conservation of mass (I will refer to this as LCM), as it would mean matter can "flow" into the universe, but not out, meaning the total matter will never be less than it was before.

The third statement violates LCM because it means matter is created during a reaction, which is not true.

The last statement violates LCM because it means matter is lost during a reaction, which is not true.

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.