Which of these substances is acidic?
Baking soda
Water
Lemon
Floor cleaner

Lemon

Explanation:

Backing soda is not acidic

Water is not acidic

Lemon is acidic since it contains citric acid

Floor cleaner can be acidic depending on its amount of cleaning chemicals.

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.