Which action is not an example of work? A. pushing a box across the floor
B. picking up a box off the floor
C. holding a tray in the Cafeteria line
D. raising a barbell over your head

C

Explanation:

holding a tray in the Cafeteria line

C. picking a tray in the cafeteria line

a patient chooses to not take a beneficial medical treatment.

explanation:

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally