Question 1 (1 point) Why is Earth considered a closed system?
Mass passes across Earth's system boundary, but not radiant energy.
Radiant energy and mass can pass across Earth's system boundary.
Radiant energy and mass cannot cross Earth's system boundary.
Radiant energy passes across Earth's system boundary, but not mass.

Radiant energy passes across Earth's system boundary, but not mass.

Explanation:

In a closed system, no substance can escape or be added to it. Energy, on the other hand, can still reach the system or leave the system again.

it should be p1 v1 = p2 v2

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.