I NEED HELP WITH SCIENCE

Both are chemical changes.

Explanation:

They are chemical changes because when when you melt the sugar to make caramel a new substance is formed. The same with cookies. You don't start out with cookies, you start out with dough. And then when you cook the dough a new substance is formed which is the cookies.

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.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.