Answer the following questions in brief.
Why does silver get tarnished on exposure to air?

When silver is exposed to sulfur-containing gases in the air, it discolours and then darkens as it reacts with the gas to form a surface layer of tarnish. This process is called tarnishing.

Hope this helped :)

they emit helium gas that attaches to nearby planets.

they remove low-mass elements from the planets’ crust.

they cause nuclear fusion inside the inner core of planets.

they produce heavy elements such as iron and gold.

explanation:

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.