Can two atoms with the same mass number ever be isotopes of each other

No, two atoms with the same mass number can never be isotopes of each other.

Explanation:

Isotopes always have different mass number and same atomic number. Mass number is the sum of the number of protons and the number of neutrons. Atomic number is the total number of protons. Therefore, isotopes have different number of neutrons but same number of protons. For example, the three isotopes of hydrogen are ¹₁H,²₁H and ³₁H.

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.

dynamic equilibrium is the answer.