Which ionic equation represents a spontaneous reaction that can occur in a voltaic cell? 1. cu(s) + zn(s) → cu2+(aq) + zn2+(aq) 2. cu(s) + zn2+(aq) → cu2+(aq) + zn(s) 3. cu2+(aq) + zn(s) → cu(s) + zn2+(aq) 4. cu2+(aq) + zn2+(aq) → cu(s) + zn(s)

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.

16

explanation:

the marks go by 4s