One radioactive isotope of calcium has an atomic mass of 47. how many protons are in this calcium-47 nucleus? a) 17 b) 20 c) 27 d) 47

B) 20

Explanation: Atomic number is equal to the number of electrons or the number of protons for a neutral atom.

Mass number is the sum of number of protons and the number of neutrons.

Mass number = Number of protons + Number of neutrons = 47

General representation of an element is given as: where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

Calcium has atomic number of 20. For the given isotope of calcium,

Thus number of protons = 20.

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.